U.S. patent application number 10/543145 was filed with the patent office on 2007-05-03 for multimedia interface device, information processing method, corresponding information carrier and computer program.
This patent application is currently assigned to Canon Eurpopa NV. Invention is credited to Stephane Bizet, Sylvain Buriau, Arnaud Closset, Laurent Frouin, Philippe Le Bars, Herve Merlet.
Application Number | 20070101042 10/543145 |
Document ID | / |
Family ID | 32669222 |
Filed Date | 2007-05-03 |
United States Patent
Application |
20070101042 |
Kind Code |
A1 |
Merlet; Herve ; et
al. |
May 3, 2007 |
Multimedia interface device, information processing method,
corresponding information carrier and computer program
Abstract
A multimedia interface device for the transfer of information in
a communications network comprises, at least two connection means
to which, respectively, at least two sending devices can get
connected by means respectively of two communications links
compliant respectively with two protocols; means of connection to a
single remote switching device by means of a single cable, the
switching device comprising at least switching means between at
least two ports; means to mix the information sent out by sending
devices into only one stream of information in the form of segments
being able to contain part of the information; and means to
transfer the stream of information in the form of segments on at
least one pair of cable to the switching device to which it is
connected according to a third protocol.
Inventors: |
Merlet; Herve; (Amstelveen,
NL) ; Bizet; Stephane; (Amstelveen, NL) ;
Frouin; Laurent; (Amstelveen, NL) ; Buriau;
Sylvain; (Amstelveen, NL) ; Le Bars; Philippe;
(Amstelveen, NL) ; Closset; Arnaud; (Amstelveen,
NL) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
Canon Eurpopa NV
Bovenkerkerweg 59-61
XB Amstelveen
NL
NL-1185
|
Family ID: |
32669222 |
Appl. No.: |
10/543145 |
Filed: |
January 22, 2004 |
PCT Filed: |
January 22, 2004 |
PCT NO: |
PCT/IB04/00858 |
371 Date: |
July 21, 2006 |
Current U.S.
Class: |
710/311 |
Current CPC
Class: |
H04L 12/40117 20130101;
H04L 12/2803 20130101; H04L 12/10 20130101; H04L 2012/644 20130101;
H04L 12/6418 20130101; H04L 12/2838 20130101 |
Class at
Publication: |
710/311 |
International
Class: |
G06F 13/36 20060101
G06F013/36 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 24, 2003 |
FR |
FR0300833 |
Claims
1. A multimedia interface device for the transfer of information in
a communications network, wherein the multimedia interface device
comprises: at least one first connection means to which at least
one first communications device, called a first sending device, can
get connected by means of a first communications link compliant
with a first protocol, at least one second connection means to
which at least one second communications device, called a second
sending device, can get connected by means of a second
communications link compliant with a second protocol, means of
connection to a single remote device by means of a single cable
constituted by at least one pair, said remote device called a
switching device comprising at least switching means between at
least two ports, means to mix the information sent out by said at
least two devices into only one stream of information in the form
of segments, each segment being able to contain part of the
information sent out by the first device and/or by the second
device, means to transfer the stream of information in the form of
segments on said at least one pair of said cable to the switching
device to which it is connected according to a third protocol
different from the first and second protocols.
2. A device according to claim 1, wherein it comprises a means to
obtain packets from the information sent out by the at least two
devices, a segment being able to contain the obtained packets or
part of the obtained packets.
3. A device according to claim 1, wherein the first protocol is a
protocol adapted to the transfer of multimedia information by
isochronous or asynchronous type data packets.
4. A device according to claim 3, wherein the first protocol is a
protocol compliant with the IEEE1394 standard.
5. A device according to claim 4, wherein the mixing means comprise
means for the reservation of bandwidth in the communications
network.
6. A device according to claim 5, wherein the bandwidth reservation
means ensure a minimum bandwidth for the isochronous type
multimedia information and ensure a maximum bandwidth for the
asynchronous type multimedia information.
7. A device according to claim 1, wherein the second protocol is a
protocol adapted to the transfer of information by Ethernet type
packets.
8. A device according to claim 1, wherein the interface device
furthermore comprises means for the reception of information coming
from the switching device to which it is connected, means to
determine the connection means to which the device that is the
destination of the information is connected and means for the
transfer of said received information to the determined connection
means.
9. A device according to claim 8, wherein the received information
coming from the switching device is in the form of segments, one
segment possibly comprising information intended for a plurality of
destination or listener devices.
10. A device according to claim 9, wherein the segments furthermore
comprise information representing the state of occupancy of the
ports of the switching device to which the device is connected.
11. A device according to claim 1, wherein the cable consists of
four pairs, two pairs dedicated to the sending of information and
two pairs dedicated to the reception of information.
12. A device according to claim 11, wherein segments are
transmitted on each of the pairs and wherein, on the transmission
pairs dedicated to sending or reception, one pair transmits
segments comprising most significant bits of the information bytes
sent by the sending devices and the other pair transmits segments
comprising least significant bits of the information bytes sent by
the sending devices.
13. A device according to claim 1, wherein the cable consists of at
least two pairs, and wherein the means of connection to the
switching device comprise, for each pair, a midpoint-grounded
transformer and wherein the interface device comprises means for
obtaining electrical power connected to said midpoints of the
transformers.
14. A device according to claim 1, wherein the cable consists of at
least two pairs, and wherein the interface device comprises means
for the connection of a telephone communications device to a
telephone line by means of midpoints of two transformers.
15. A device according to claim 13, wherein the cable consists of
four pairs, two pairs being dedicated to the sending of information
and two pairs being dedicated to the reception of information, the
connection means of the telephone communications device are
connected to the telephone line by means of midpoints of the
transformers associated with the pairs dedicated to the
transmission or reception of information, the means for obtaining
electrical power are connected to said midpoints of the other
transformers.
16. A device according to claim 1, wherein the means of connection
to a single remote device comprises a wall socket, integrated in a
wall and connected to the single remote device and to the
multimedia device by means of a single medium.
17. A device according to claim 16, wherein the multimedia
interface device is located, outside the wall, on one side of the
wall and the remote device is located on the other side of the
wall.
18. A device according to claim 16, wherein the single medium is a
CAT 5 type cable and the wall socket is a RJ 45 type socket.
19. A device according to claim 16, wherein the wall socket is
connected to the single remote device through a multiple rack by
means of a single medium, the multiple rack being connected to a
plurality of wall sockets, and selectively allowing one of the
plurality of the wall sockets to communicate with the single remote
device.
20. A device according to claim 19, wherein the multimedia
interface device is located, outside the wall, on one side of the
wall and the remote device and the multiple rack are located on the
other side of the wall.
21. A device according to claim 1, wherein the multimedia interface
device comprises filtering means to filter signals coming from a
telephone communications device connected to said at least one pair
of the single cable.
22. A switching device for the transfer of information in a
communications network, wherein the switching device comprises:
means of connection to at least one remote multimedia interface
device by means of a single cable consisting of at least one pair,
at least two communications ports with which information storage
means are associated, it being possible to connect the
communications ports to a second switching device or to a second
multimedia interface device, switching means to transfer the
information between the ports and/or between the connection means
and to at least one of the ports, means for obtaining information
representing the quantity of information contained in the
information storage means, means for the transfer of the
information obtained towards said at least one device to which the
switching device is connected.
23. A device according to claim 22, wherein the information
transferred to said at least one multimedia interface device is in
the form of segments, one segment possibly comprising information
intended for a plurality of reception devices connected to said at
least one multimedia interface device.
24. A device according to claim 22, wherein the cable consists of
four pairs, two pairs dedicated to the sending of information and
two pairs dedicated to the reception of information.
25. A device according to claim 24, wherein segments are
transmitted on each of the pairs and wherein, on the two
transmission pairs dedicated to sending or reception, one pair
transmits segments comprising most significant bits of the
information bytes sent by the sending devices and the other pair
transmits segments comprising least significant bits of the
information bytes sent by the sending devices.
26. A device according to claim 24, wherein the means of connection
to the switching device comprise, for each pair, a midpoint
transformer and wherein the interface device comprises means for
obtaining electrical power connected to said midpoints of the
transformers.
27. A device according to claim 24, wherein the switching device
comprises means for the connection of a public telephone line to
the midpoints of two transformers.
28. A device according to claim 27, wherein the means of connection
of a public telephone line connect the public telephone line by
means of midpoints of the transformers associated with the pairs
dedicated to the transmission or reception of information, the
means for providing electrical power being connected to said
midpoints of the other transformers.
29. A device according to claim 22, wherein the switching device
comprises filtering means to filter signals coming from a telephone
communications device connected to said at least one pair of the
single cable.
30. A method for the processing of information in a multimedia
interface device for the transfer of information in a
communications network, the multimedia interface device comprising
at least one first connection means to which at least one first
communications device, called a first sending device, can be
connected by means of a first communications link compliant with a
first protocol, at least one second connection means to which at
least one second communications device, called a second sending
device, can get connected by means of a second communications link
compliant with a second protocol, means of connection to a single
remote device by means of a single cable constituted by at least
one pair, said remote device called a switching device comprising
at least means of switching between at least two ports and wherein
the method comprises the steps of: the mixing of the information
sent by said at least two sending devices into only one stream of
information in the form of segments each segment being able to
contain part of the information sent out by the first device and/or
by the second device; and the transfer of the stream of information
in the form of segments on said at least one pair of said cable to
the switching device to which it is connected according to a third
protocol different from the first and second protocols.
31. A method according to claim 30, wherein it comprises the step
of obtaining packets from the information sent out by the at least
two devices, a segment being able to contain the obtained packets
or part of the obtained packets.
32. A method according to claim 30, wherein the first protocol is a
protocol adapted to the transfer of multimedia information by
isochronous or asynchronous type data packets.
33. A method according to claim 32, wherein the first protocol is a
protocol compliant with the IEEE1394 standard.
34. A method according to claim 33 wherein, during the mixing step,
a bandwidth reservation is made in the communications network.
35. A method according to claim 34, wherein the bandwidth
reservation means ensure a minimum bandwidth for the isochronous
type multimedia information and ensure a maximum bandwidth for the
asynchronous type multimedia information.
36. A method according to claim 30, wherein the second protocol is
a protocol adapted to the transfer of information by Ethernet type
packets.
37. A method according to claim 30, wherein the method furthermore
comprises a step for the reception of information coming from the
switching device to which the interface device is connected, a step
to determine the connection means to which the device that is the
destination of the information is connected and a step for the
transfer of said received information to the determined connection
means.
38. A method according to claim 37, wherein the received
information coming from the switching device is in the form of
segments, one segment possibly comprising information intended for
a plurality of destination or listener devices.
39. A method according to claim 38, wherein the segments
furthermore comprise information representing the state of
occupancy of the ports of the switching device to which the device
is connected.
40. A totally or partially detachable information carrier, which
can be read by a computer system, wherein the information carrier
contains instructions from a computer program, enabling the
implementation of a processing method according to claim 30.
41. A computer program stored in any information carrier, said
program comprising instructions to implement the processing method
according to claim 30, when it is loaded and executed by a computer
system.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a communications network
enabling the connection of a plurality of devices that process data
in different formats. More particularly, the invention is situated
in the framework of a home type network.
[0003] 2. Description of the Prior Art
[0004] The modern devices with which a family may be equipped often
have to transmit different types of data such as video, sound,
photos, text files etc. and the like. The transmission of this data
is governed by requirements that are variable depending on the type
of data considered. This data must be conveyed especially by means
of cables or adapted links. Thus, each data format has a
corresponding adapted means of transportation and a type of
connector used to connect devices with one another. For example,
devices processing digital data may work according to the IEEE-1394
standard.
[0005] In order to extend the possibilities of interconnection of
devices in a house, there are networks comprising nodes in which
interfaces are designed are with different connectors such as, for
example, 1394 type connectors, Ethernet type connectors which
enable the connection of the corresponding devices. This enables
the networking of several devices. However, the connections must be
made on one of the nodes of the network or on a hub. The data is
then processed independently. There is no provision for conveying
several types of data together, on the same transportation means.
If the interface comprising several connectors has to be shifted to
a wall socket, then it will be necessary to provide as many
transportation means, such as cables, as there are different
connectors. For cabling in a house, it becomes cumbersome to make
several cables go through the walls.
[0006] The publication "Home information wiring system using UTP
cables for IEEE 1394 and Ethernet systems" in the journal IEEE
transactions on Consumer Electronics Vol. 47, No. 4, November 2001,
describes an adapter which can be used to connect an IEEE1394 cable
and an Ethernet cable to an UTP 5 cable comprising four twisted
pairs. To do this, the above-mentioned article describes the use of
two twisted pairs to obtain the passage of an IEEE1394 signal and
two other twisted pairs to obtain the passage of an Ethernet
signal.
[0007] This publication does not describe the possibility of
bringing about the transit, on this same cable, of other data
having different formats such as telephone type data.
[0008] Furthermore, the transmission of IEEE1394 or Ethernet type
data is limited in this case to 100 Mbps. Now, the fact is that use
of these protocols in the context of home applications requires far
greater transmission capacity, especially for video applications.
Furthermore, this distribution of the data requires an equitable
sharing of the bandwidth between all the data formats: this is not
always so in reality. Indeed, it is sometimes necessary to plan for
a bandwidth that is dynamically greater for one type of data as
compared with another type of data.
[0009] The different types of data that may travel in a home
network have variable requirements in order to be transmitted.
Thus, the transfer of video type data for example necessitates a
particular, continuous bit rate. The same is true for sound. In
this case, it is said that the data is isochronous data. On the
contrary, for a text file, the data does not need to be transmitted
continuously or even regularly. In this case, it is said that the
data is asynchronous data. Another example of asynchronous data
consists of the commands to turn various apparatuses on or off, and
also data intended for printers. A home network must therefore be
able to obtain the transit of the asynchronous data as well as
isochronous data, this isochronous data having to travel at certain
variable speeds and bit rates.
[0010] The patent application EP1124357, describes a communications
network in which the communications nodes interconnect different
IEEE1394 type networks by means of a switched network.
[0011] The nodes comprise IEEE1394 type interfaces with a switching
unit comprising three input/output ports. They transfer the
IEEE1394 packets by one of the input/output ports and send it to
another communications node.
[0012] The fact is that the configuration of these nodes is not
particularly suited to a simple installation in a home
environment.
[0013] Indeed, the communications nodes as described comprise a
plurality of IEEE1355 type connections, and therefore a large
number of cables are necessary to provide for the efficient
operation of this network.
[0014] This large number of cables and connections to be set up
makes it difficult to install a network of this kind and above all
generates problems of positioning cables and obtaining their
passage in a home environment.
[0015] Furthermore, the technologies related to the transmission of
multimedia information are developing very rapidly, and it is
therefore necessary to envisage communications network that can be
easily upgraded.
[0016] Thus, if new interconnection standards appear, the possessor
of such a network will find it necessary to change all the
communications nodes even though only one sub-part of these nodes
needs to be modified.
[0017] The cost associated with this modification therefore entails
penalties for the possessor of this network.
SUMMARY OF THE INVENTION
[0018] The invention seeks to resolve the drawbacks of the prior
art by proposing a multimedia interface device for the transfer of
information in a communications network, wherein the multimedia
interface device comprises: [0019] at least one first connection
means to which at least one first communications device, called a
first sending device, can get connected by means of a first
communications link compliant with a first protocol, [0020] at
least one second connection means to which at least one second
communications device, called a second sending device, can get
connected by means of a second communications link compliant with a
second protocol, [0021] means of connection to a single remote
device by means of a single cable constituted by at least one pair,
said remote device called a switching device comprising at least
switching means between at least two ports, [0022] means to mix the
information sent out by said at least two devices into only one
stream of information in the form of segments, each segment being
able to contain part of the information sent out by the first
device and/or by the second device, [0023] means to transfer the
stream of information in the form of segments on said at least one
pair of said cable to the switching device to which it is connected
according to a third protocol different from the first and second
protocols.
[0024] Thus, the separation of the multimedia interface device and
of the switching device makes it easier to set up a network of this
kind. The multimedia interface device placed in the vicinity of the
information sources will enable the mixing of this information so
that it can be transmitted by means of a single medium.
[0025] The remote switching device could also be positioned in such
a way as to enable the making of a network topology in a star
configuration.
[0026] Finally, if the new interconnection standards appear, only
the multimedia interface device would have to be replaced or
modified.
[0027] In a particular embodiment, the device comprises a means to
obtain packets from the information sent out by the at least two
devices, a segment being able to contain the obtained packets or
part of the obtained packets.
[0028] More specifically, the first protocol is a protocol adapted
to the transfer of multimedia information by isochronous or
asynchronous type data packets. It is for example compliant with
the IEEE1394 standard.
[0029] More specifically, the means used for mixing comprise means
for the reservation of bandwidth in the communications network.
These bandwidth reservation means ensure a minimum bandwidth for
the isochronous type multimedia information and ensure a maximum
bandwidth for the asynchronous type multimedia information.
[0030] In a particular embodiment, the second protocol is a
protocol adapted to the transfer of information by Ethernet type
packets.
[0031] According to another particular embodiment, the interface
device furthermore comprises means for the reception of information
coming from the switching device to which it is connected, means to
determine the connection means to which the device that is the
destination of the information is connected and means for the
transfer of said received information to the determined connection
means.
[0032] According to a particular embodiment, the segments
furthermore comprise information representing the state of
occupancy of the ports of the switching device to which the device
is connected. This will enable optimum management of the resources
of the switching device and will prevent the problems of saturation
of the communications ports.
[0033] According to another particular embodiment, the cable
consists of four pairs, two pairs dedicated to the sending of
information and two pairs dedicated to the reception of
information, and on the transmission pairs dedicated to sending or
reception, one pair transmits segments comprising most significant
bits of the information bytes sent by the sending devices and the
other pair transmits segments comprising least significant bits of
the information bytes sent by the sending devices.
[0034] More specifically, the means of connection to the switching
device comprise, for each pair, a midpoint-grounded transformer and
the interface device comprises means for obtaining electrical power
connected to said midpoints of the transformers.
[0035] In a particular embodiment, the interface device comprises
means for the connection of a telephone communications device to a
telephone line by means of midpoints of two transformers.
[0036] According to another particular embodiment, the means of
connection to a single remote device comprises a wall socket,
integrated in a wall and connected to the single remote device and
to the multimedia device by means of a single medium.
[0037] More specifically, the multimedia interface device is
located, outside the wall, on one side of the wall and the remote
device is located on the other side of the wall.
[0038] More specifically, the single medium is a CAT 5 type cable
and the wall socket is a RJ 45 type socket.
[0039] More specifically, the wall socket is connected to the
single remote device through a multiple rack by means of a single
medium, the multiple rack being connected to a plurality of wall
sockets, and selectively allowing one of the plurality of the wall
sockets to communicate with the single remote device.
[0040] Finally, the multimedia interface device is located outside
the wall, on one side of the wall and the remote device and the
multiple rack are located on the other side of the wall.
[0041] According to another particular embodiment, the multimedia
interface device comprises filtering means to filter signals coming
from a telephone communications device connected to said at least
one pair of the single cable.
[0042] Correlatively, the invention proposes a switching device for
the transfer of information in a communications network, wherein
the switching device comprises: [0043] means of connection to at
least one remote multimedia interface device by means of a single
cable consisting of at least one pair, [0044] at least two
communications ports with which information storage means are
associated, it being possible to connect the communications ports
to a second switching device or to a second multimedia interface
device, [0045] switching means to transfer information between the
ports and/or between the connection means and to at least one of
the ports, [0046] means for obtaining information representing the
quantity of information contained in the information storage means,
[0047] means for the transfer of the information obtained towards
said at least one device to which the switching device is
connected.
[0048] In one variant, the means of connection to the switching
device comprise, for each pair, a midpoint-grounded transformer and
the interface device comprises electrical power supply means
connected to said midpoints of the transformers.
[0049] Correlatively, the invention proposes a method of
information processing in a multimedia interface device for the
transfer of information in a communications network, the multimedia
interface device comprising at least one first connection means to
which at least one first communications device, called a first
sending device, can be connected by means of a first communications
link compliant with a first protocol, at least one second
connection means to which at least one second communications
device, called a second sending device, can get connected by means
of a second communications link compliant with a second protocol,
means of connection to a single remote device by means of a single
cable constituted by at least one pair, said remote device called a
switching device comprising at least means of switching between at
least two ports and wherein the method comprises the steps of:
[0050] the mixing of the information sent by said at least two
sending devices, [0051] the transfer of the mixed information on
said at least one pair of said cable to the switching device to
which it is connected according to a third protocol different from
the first and second protocols.
[0052] The invention also relates to a totally or partially
detachable information carrier, which can be read by a computer
system, wherein the information carrier contains instructions from
a computer program, enabling the implementation of the method as
described here above.
[0053] The invention also relates to the computer program stored in
any information carrier, said program comprising instructions with
which to implement the processing method described here above, when
it is loaded and executed by a computer system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] Other particular features and advantages of the invention
shall appear from the following description, made with reference to
the appended drawings, of which:
[0055] FIGS. 1a shows a communications system according to the
invention;
[0056] FIG. 1b and 1c show alternative embodiments of the
communications system according to the invention;
[0057] FIG. 2 is a block diagram representing the main constituent
elements of the interface devices and switching devices;
[0058] FIG. 3 is a block diagram of an audio/video interface module
contained in a multimedia interface device;
[0059] FIG. 4 is an electrical diagram of the audio/video network
module contained in the switching device;
[0060] FIG. 5 is a block diagram of a Y link interface included in
the multimedia interface device and the switching device;
[0061] FIG. 6 shows a first variant of the physical interface
module connecting the Y link interface and the transmission medium
in the switching device;
[0062] FIG. 7 shows the physical interface module connecting the Y
link interface and the transmission medium in the multimedia
interface device;
[0063] FIG. 8 shows the format of a segment transmitted on the
transmission medium;
[0064] FIG. 9 describes the state machine associated with the data
transmission module 512 described in FIG. 5.
[0065] FIG. 10 shows a second variant of the physical interface
module connecting the Y link interface and the transmission medium
in the switching device;
[0066] FIG. 11a is an electrical diagram of the low-pass filter
connected according to the second variant of the physical interface
module;
[0067] FIG. 11b is an electrical diagram of the bandwidth filter
according to the second variant of the physical interface
module.
MORE DETAILED DESCRIPTION
[0068] FIG. 1a shows a multimedia communications network according
to the invention. This network is installed, for example, in a home
environment.
[0069] This multimedia communications network interconnects
equipment such as television sets referenced 103a, 103b, 103c and
103d, videocassette recorders referenced 107 and 110, DVD type
readers referenced 108 and 109.
[0070] Computer type devices referenced 112 and 115 may also be
connected to this network.
[0071] To these computers, it is also possible to connect, for
example, a digital camera referenced 111.
[0072] According to the invention, this network comprises
multimedia interface devices referenced 102a 102b, 102c and 102d.
The multimedia interface device 102a is connected to a switching
device 100a by means of a single medium, in the present case a
cable 101a.
[0073] This same switching device 100a is connected to other
switching devices referenced 100b, 100c and 100d. The switching
device 100a is connected by means of a cable 113a to the switching
device 100d. It is also connected by means of another cable 113d to
the switching device 100c which is itself connected by another link
113e to the switching device 100d.
[0074] The switching device 100c is connected to the switching
device 100b by means of a link 113c and finally the switching
device 100b is connected to the switching device 100a by means of a
communications link 113b.
[0075] It must be noted that the communications devices 100a, 100b,
100c and 100d are inserted according to a particular mode of the
invention in the partition walls of a dwelling.
[0076] The device 100a is placed, for example, in the partition
wall 120a of a room such as a living room, the device 100b in the
partition wall 120b of another room such as the kitchen and the
device 100c in the partition wall 120c of a room such as a study,
the device 100d in the partition wall 120d of a bedroom.
[0077] The multimedia interface device 102a is connected by means
of an analog video link 105a to the television set 103a. The
multimedia interface device 102a is also connected by means of a
link 130a according to the standard IEEE1394 to an analog-digital
converter which is itself connected to a video cassette recorder
107 by means of a link 106a.
[0078] The multimedia interface devices 102a, 102b, 102c and 102d
are respectively connected to the switching devices 100a, 100b,
100c and 100d by means of transmission media which are more
particularly CAT5 type cables 101a, 101b, 101c and 101d consisting
of four pairs of twisted wires. This type of cable is classically
used in Ethernet type networks.
[0079] It must be noted that other media could be used, for example
fiber-optic links or cables according to the IEEE1355 standard.
[0080] The CAT5 type cables 101a, 101b, 101c and 101d are
particularly well suited to the invention because they are very
widely used and very reasonably priced.
[0081] The analog television sets 103b, 103c and 103d are
respectively connected to the multimedia interface devices 102b,
102c and 102d respectively by links 105b, 105c and 105d identically
to the link 105a connecting the analog television set 103a and the
multimedia interface device 102a.
[0082] The multimedia interface device 102b is connected by an IEEE
1394 type link referenced 130b to an analog/digital converter 104b
which will generate the analog video information generated by the
DVD reader 108 in a format compatible with the IEEE1394 standard.
The DVD reader 108 is connected to the analog/digital converter
104b by an analog link 106b comprising RCA type connectors.
[0083] The multimedia interface device 102b is connected by a
second link 130c, identical to the link 130b, to an analog-digital
link 104c identical to the converter 104b itself connected to a DVD
reader 109 by means of a link 106c. Since the connections are
identical to those described earlier, they shall not be described
in greater detail. It must be noted that any type of device that
generates analog information, for example a camera or a microphone,
can be connected to the analog-digital converter 104c.
[0084] The multimedia interface device 102c is connected by means
of an Ethernet type link 116a to a computer 112.
[0085] The multimedia interface device 102c has a second computer
115 connected to it by an IEEE 1394 type link referenced 130d. This
computer 115 also has a digital camcorder 111 connected to it by
means of an IEEE 1394 type link referenced 130e and an analog video
tape recorder 110 connected to it by means of an analog-digital
converter 104d identical to the converter 104c described here
above. Since the link 130f is identical to the link 130c, it shall
not be described. This is also the case for the link 106d with the
link 106b.
[0086] It must be noted that each of the multimedia interface
devices described here above comprises at least connection means of
the Ethernet and IEEE1394 types and at least one analog video
output. All the information obtained or delivered by this
connection means will be distributed to other remote multimedia
interface devices by means of a single CAT5 type cable.
[0087] This cable 101a will greatly simplify the installation of
such a network in a home environment. Indeed, only one cable will
be needed to connect the multimedia interface device 102a to the
wall socket 100a. This is also the case for the cables 101b, 101c
or 10d.
[0088] The wall sockets 100a, 100b, 100c and 100d comprising
communications means and several input/output ports will be
interconnected by means of multiple connections enabling efficient
routing of the data. Since these multiple connections are
integrated into the infrastructure of the house, they will not be a
source of inconvenience to the user of such a network.
[0089] Referring to FIG. 1b, we shall now describe a variant of the
invention. In FIG. 1b the multimedia interface devices referenced
102a, 102b and 102c of FIG. 1a are respectively integrated into the
partition walls 120a, 120b and 120c. They are referenced 150a, 150b
and 150c in FIG. 1b. The multimedia interface device 102d of FIG.
1a is not integrated into the wall. It is referenced 150d in FIG.
1b. The switching devices 100a, 100b, 100c and 100d for their part
are grouped in a central switching unit 160 preferably placed
beside the power supply panel. This configuration brings numerous
advantages: indeed a single medium and more specifically a single
cable, respectively 160a, 160b, 160c, 160d and 160e will connect
the different parts of the house to the central switching unit 160.
This will simplify the installation of the network and also reduce
its cost. The link 160d is connected to a classic RJ45 type wall
socket 150e and is extended by an external link 160e.
[0090] The interconnections referenced 113a, 113b, 113c, 113d and
113e in FIG. 1a will be set up in the central switching unit 160.
For simplicity's sake, they are not shown here.
[0091] The links 105i, 105j, 105k and 105l are identical to the
links 105a, 105b, 105c and 105d of FIG. 1a and shall not be
described in greater detail.
[0092] The links 130k, 130l, 130m and 130n are identical to the
links 130a, 130b, 130c and 130d of FIG. 1a and shall not be
described in greater detail.
[0093] The link 116b is identical to the link 116a of FIG. 1a, and
shall not be described in greater detail.
[0094] The devices such as the television sets, video cassette
recorders, analog/digital converters, DVD readers, camcorders and
micro-computers as well as the associated links are identical to
those described with reference to FIG. 1a and shall not be
described in greater detail.
[0095] According to another variant, not shown in the figure, the
multimedia devices 150a, 150b, 150c are not integrated into the
partition walls, this being done in the same way as the multimedia
interface 150d. These interfaces are connected respectively by
means of a single medium, more specifically a CAT5 type cable, to
an RJ45 type wall socket.
[0096] These same wall sockets are respectively connected by means
of a CAT5 type cable to the central switching unit 160 preferably
placed beside the power supply cable.
[0097] When a dwelling has a pre-existing type of Ethernet network
using the same type of cable as the one used in this invention,
this variant will enable this pre-existing network to be upgraded
into a network according to the invention.
[0098] This upgrading or development will then consist of the
replacement of the hub of the pre-existing Ethernet network by a
central switch unit and the connection of the multimedia interfaces
150a, 150b, 150c and 150d to the RJ45 type wall sockets.
[0099] Thus, the wiring of the dwelling does not have to be
modified, and nor do the wall sockets.
[0100] According to another variant, shown in FIG. 1c, users are
offered the possibility to select one wall socket of RJ 45 type
among a set of wall sockets for connecting multimedia interfaces.
In FIG. 1c, the room 121 comprises several wall sockets disposed at
different location within the room. The wall sockets 150e1, 150e2
and 150e3 are connected to a multiple rack 161, by means of single
CAT 5 cables 160d1, 160d2 and 160d3, respectively. The multiple
rack 161 is itself connected, by means of single medium 160d, such
as a CAT5 type cable, to the central switching device 160. The
multimedia interface 150d, not integrated to the wall, is connected
by a means of a single medium 160e, more specifically a CAT5 type
cable, to the RJ 45 type wall socket 150e.
[0101] The multiple rack 161 consists of a passive switching system
that allows only one of the wall sockets 150e1, 150e2, 150e3
connected to the multiple rack 161, to be connected, at a time, to
the central switching unit 160. As an example, as shown in FIG. 1c,
only the wall socket 150e is connected to the central switching
unit 160. In order to connect a wall socket other than the wall
socket 150e1 to the central unit 160, it is necessary to modify the
switch connection of the multiple rack 161. The modification of the
switch connection of the multiple rack means the disconnection
between the wall socket 150e1 and the central. In such a way, the
multimedia interface 150d can be connected to another wall socket,
within the room 121, as long as the switch connection of the
multiple rack is modified, so that this particular wall socket is
connected to the central switch.
[0102] Such implementation provides a better flexibility for the
installation of appliances within a room. It further removes the
obligation of directly connecting all the different several socket
walls to the central switching unit and allows the use of less
complex and less expensive central-switching units.
[0103] It should be understood that a multiple rack could be
associated to one room or more. Similarly two or more multiple
racks might be necessary to connect all the wall sockets of one
room to the central switching unit.
[0104] Referring to FIG. 2, we shall now describe a block diagram
representing the main constituent elements of the multimedia
interface devices and switching devices according to the
invention.
[0105] The central switching device 160 as described in FIG. 1b is
formed by four switching devices referenced 250a, 250b, 250c and
250d. These switching devices are similar to the devices 100a,
100b, 100c and 100d described with reference to FIG. 1a. These four
communications devices are interconnected by links referenced 113a,
113b, 113c, 113d and 113e. These interconnections are identical to
those described with reference to FIG. 1a, and shall not be
described in greater detail.
[0106] The switching device 250a consists of a first interface
module 203 called a Y link interface module, which shall be
described in greater detail with reference to FIG. 5.
[0107] The switching device 250a furthermore comprises a second
module 202 which is an audio/video module. This module shall be
described in greater detail with reference to FIG. 4.
[0108] Finally, the switching device comprises interface modules
201a, 201b and 201c called X link modules.
[0109] It must be noted that the modules of 201a, 201b and 201c are
similar to the module 203. It must also be noted that since the
length of the links 113a, 113b, 113c, 113d and 113e is appreciably
smaller than that of the links 160a, 160b, 160c and 160d,
transmission bit rates on the links 113a, b, c, d and e could be
far greater than those that can be envisaged on the links 160a,
160b, 160c and 160d which are about 100 Mbps.
[0110] The devices 250b, 250c and 250d are identical to the device
250a, and shall not be described in greater detail.
[0111] The switching devices 250a, 250b, 250c and 250d have
multimedia interface devices respectively 150a, 150b, 150c and 150d
connected to them respectively by means of a single cable 160a,
160b, 160c and 160d. The cable 160d is of course extended by a
connector 150e and a cable 160e as described with reference to FIG.
1b. The multimedia interface device 150a consists of two modules
referenced 204 and 205. The interface module 204, called a Y link
interface module is identical to the module 203. The interface
module 205, called an audio/video interface module, shall be
described in greater detail with reference to FIG. 3.
[0112] FIG. 3 is the block diagram of an audio/video interface
module included in a multimedia interface device 150a, 150b, 150c,
150d or 102a, 102b, 102c, 102d.
[0113] In general, an audio/video interface has a plurality of
connection means by which signals of different kinds will be
processed. The data coming from these connection media will be
mixed with each other to form only one data stream compliant with a
different protocol that is transmitted by means of the Y link
interface on the single medium which, in the present case, is a
CAT5 cable.
[0114] This audio/video interface 205 will also manage the QoS
(quality of service) associated with its different signals.
[0115] The audio/video interface has a microcontroller 338 which
will transfer data on the bus 320 to RAM (Random Access Memory)
type storage means 306 more particularly when the data comes from
the link 160a.
[0116] When the multimedia interface device is powered on, the
microcontroller 338 will load the program contained in the flash
memory 305 into the RAM 306 and execute the code associated with
this program.
[0117] The microcontroller 338 will transfer information coming
from the different connection means to a transmission queue
referenced 301.
[0118] This information will be transferred to the transmission
queue 301 according to the quality of service required for the
transfer of this information.
[0119] Indeed, the IEEE1394 type networks enable the exchange of
isochronous or asynchronous type data. Isochronous data (which is
the case here) is governed by transmission bit rate imperatives
while asynchronous type data may be transmitted without being
governed by transmission bit rate imperatives.
[0120] The transfer of data according to Quality of Service
requirements is described in the European patent application No.
01400316 and shall not be described in greater detail in this
document.
[0121] The microcontroller 338 has a 100 baseT type Ethernet
interface 316 connected to it. This interface 316 enables the
connection of the cable 116a or 116b described here above with
reference to FIGS. 1a and 1b
[0122] A character generator 317, or on-screen display unit, is
also connected to the microcontroller 338. This character generator
317 will enable the insertion of information, into the video signal
transmitted on the link 105a for example.
[0123] An infrared transmission and reception module 318 is also
connected to the microcontroller 338. Through this infrared module
318, infrared control signals coming from a remote control unit
will be retransmitted by means of the microcontroller 338 to the
different devices connected to the network. This transfer of
infrared commands is described in the French patent application No.
0110367.
[0124] It must be noted that, in one variant, the infrared module
is preferably a one-way device.
[0125] Through the bus interface 304, the microcontroller 338 will
also manage the configuration of the transmission parameters
associated with each transmission queue, these parameters being
stored in the segmentation and reassembly module 303.
[0126] For the transmission queues associated with an isochronous
data stream (i.e. "stream mode buffer" type queues), the
segmentation and reassembly module 303 ensures the minimum
transmission bit rate necessary for the isochronous type data
stream from the transmission parameters.
[0127] For the transmission queues associated with an asynchronous
type data stream (i.e. "message mode buffer" type queues), the
segmentation and reassembly module 303 ensures a maximum
transmission bit rate for the asynchronous type data from the
transmission parameters.
[0128] The parameters of transmission by the microcontroller 338,
associated with each transmission queue, are computed: [0129] as a
function of a bandwidth reservation in the network for "stream mode
buffer" type queues; [0130] locally as a function of an estimation
of the bandwidth available in the network for the "message mode
buffer" type queues.
[0131] The transfer of data according to these two modes of
transmission is described in the European patent application No.
01400316 and shall not be described in greater detail in this
document.
[0132] This data will come either from devices connected to the
IEEE 1394 links referenced 130k, or from an analog device such as a
VHS type video cassette recorder connected to the analog/digital
converter 314, or a micro-computer type device connected to the
Ethernet interface 316.
[0133] Should analog data come, for example, from a videocassette
recorder 107, this data will be converted by the analog/digital
converter 314 and then encoded in an MPEG2 or DV type format by the
module 313. DV is the abbreviated form of the SD-DVCR (Standard
Definition Digital Video Cassette Recorder) format. MPEG2 is the
acronym for the Motion Picture Expert Group 2. It must be noted
that the analog/digital converter 104a shown in FIG. 1a is
integrated here with the multimedia interface device 150a.
[0134] This encoded data will then be transmitted by means of the
digital audio/video interface 309 and the bridge controller 308 to
the transmission queue 301.
[0135] Should data come from a device connected to the IEEE1394
type link referenced 130k, two types of processing will be carried
out depending on the nature of the data.
[0136] If this data is asynchronous type data, it will travel
through the bus interface 304 and be memorized in the memory
306.
[0137] The microcontroller 338 transfers this data to a "message
mode buffer" type of transmission queue 301.
[0138] If the data is isochronous type data, it will travel
directly to a "stream mode buffer" type of transmission queue
301.
[0139] The microcontroller 338 will also carry out the management,
through the bus interface 304, of the distribution of data received
by means of the Y link interface 204 and stored in the reception
queue 302.
[0140] For isochronous type data and depending on the destination
of this data, the microcontroller 338 will activate the transfer of
the data either to the IEEE1394 type link controller referenced 310
if the data is intended for at least one of the terminals connected
to the bus 130k for example, or to the bridge controller 308 if
this data is addressed to a terminal connected to the link 105a for
example.
[0141] For asynchronous type data, the microcontroller 338 will
activate the transfer of the data to the RAM 306 through the bus
interface 304. The Ethernet type asynchronous data will then be
sent to the interface 116a.
[0142] The IEEE1394 type asynchronous data will then be sent to the
interface referenced 311.
[0143] If the data is intended for a terminal connected to the link
105a for example, the microcontroller 338 will activate the
transfer of this data to the audio/video digital interface 309 by
means of the bridge controller 308. This MPEG2 or DV type data will
then be decoded by the decoder 312 and finally transmitted to the
analog/digital converter 340.
[0144] The segmentation and reassembly module 303 controls the
sending of the data in the form of packets from the transmission
queues towards the Y link interface 204. Each packet comprises a
routing header as well as a packet type header (of the "message" or
"stream" type depending on the transmission queue). The routing and
packet type information is configured by the microcontroller
338.
[0145] Furthermore, the segmentation and reassembly module 303
controls the reception of the packets from the Y link interface 204
in order to store the data as a function of the type of packet in
the appropriate reception queue which is either a "message mode
buffer" or a "stream mode buffer" type of reception queue.
[0146] The decoder 312 will decode the information encoded either
in a DV type format or in an MPEG2 type format. A digital/analog
converter 340 is associated with this decoder and enables the
transfer of the information in analog form to an analog television
set 103a by means of a link 105a.
[0147] FIG. 4 shows the electrical diagram of the audio/video
network module 202 whose task is to carry out the switching of the
data, included in the switching device 250a.
[0148] The audio/video network module 202 is connected to the X
link interfaces 201a, 201b and 201c as well as to the Y link
interface 203.
[0149] Each X link interface 201a, 201b and 201c has an associated
reception memory respectively 401a, 401b and 401c and a
transmission memory, respectively 402a, 402b and 402c. They are all
FIFO type memories.
[0150] These memories are controlled by a control module referenced
408 which, firstly, controls the different operations of reading
the FIFOs 401a, 401b and 401c and sending information to the bus
405 (referenced Tx Bus) or 406 (referenced Rx Bus) and, secondly,
controls the operations for writing the data on the bus 405 to the
FIFOs 402a, 402b and 402c.
[0151] Furthermore, the control module 408 also manages: [0152] the
reception of packets between an X link interface (201a, 201b and
201c) and its associated reception FIFO (respectively 401a, 401b
and 401c). [0153] the sending of packets to the X link interface
(201a, 201b and 201c) and its associated transmission FIFO
(respectively 402a, 402b and 402c).
[0154] The Y link interface 203 has three output memories 403a,
403b and 403c as well as three input memories 404a, 404b and 404c
associated with it.
[0155] The three output memories 403a to 403c are connected through
a bus 430a (MUX bus) to the Y link interface 203.
[0156] The three input memories 404a, 404b and 404c are connected
through a bus 430b (DEMUX bus) to the Y link interface 203.
[0157] These memories are controlled by a control module referenced
410 which, firstly, controls the different operations for reading
the FIFOs 404a, 404b and 404c and sending information to the bus
405 (Tx Bus), and, secondly, controls the operations for writing
the data present on the bus 406 (Rx Bus) to the FIFOs 403a, 403b
and 403c.
[0158] Furthermore, the control module 410 manages: [0159] the
reception of packets between the Y link interface 203 and the
internal reception FIFOs (called input memories) 404a, 404b and
404c. [0160] the sending of packets to the Y link interface 203 and
the internal sending FIFOs (called output memories) 403a, 403b and
403c.
[0161] The input memories are selected by the control module
referenced 410 as a function of the FIFO or buffer address
information, extracted by the Y link interface 203.
[0162] An arbitration module 407 will control the connections
between the different FIFOs. This arbitration module 407 controls
the reading and writing in the above-mentioned memories by means of
tristate buffers referenced 420a to 420i. These buffers, under the
control of the arbitration module 407, will enable the exchange of
the data contained in the memories 401a to 401c and 402a to 402c on
a first transmission bus 405 or on a reception bus 406.
[0163] This arbitration module 407 will enable the transfer of
information between, for example, the reception memory 401a and the
transmission memory 402b or the transfer of information between,
for example, the reception memory 401a and the output memory
403a.
[0164] The arbitration module 407 interconnects the different FIFOs
from information transmitted by the header analyzer 409.
[0165] For the packet transmission between the Y link interface 203
and one or more of the X link interfaces 201a, 201b, 201c, this
interconnection is predefined independently of the contents of the
packet routing header. Thus a packet stored in the FIFO 404c (and
404b, 404a respectively) will be systematically transmitted to the
FIFO 402c (402b, 402a respectively). Similarly, a packet stored in
the FIFO 401a (and 401b, 401c respectively) and intended for the Y
link interface Y 203 will be systematically transmitted to the FIFO
403a (and 403b, 403c respectively).
[0166] The header analyzer 409 will analyze the arrived data
packets by analyzing the addresses contained in the headers of the
packets and will generate FIFO interconnection requests intended
for the arbitration module as a function of these addresses.
[0167] FIG. 5 is a synoptic view of a Y link interface 203. It must
be noted that the X link interfaces 201a, 201b and 201c are similar
to a Y link interface and shall therefore not be described.
[0168] The Y interface link described here is identical, whether it
is in a video interface module 150a, 150b, 150c, 150d or in a
switching module 250a , 250b, 250c and 250d.
[0169] The Y link interface 203 is connected for example to the
transmission medium 160a. This link is set up by means of a
physical interface module 550 described here below with reference
to FIG. 6 in a first variant or with reference to FIG. 11 in a
second variant.
[0170] This physical interface module 550 has a reception
synchronization block 500 connected to it. This block 500
determines the binary value associated with each period of the
signal received on a pair. It furthermore determines the start of
the segment and informs the de-serialization block 501a and 501b of
the binary value associated with each signal period received at the
corresponding reception pair. One period corresponds to a cycle of
125 microseconds.
[0171] It must be noted that the data reaches the synchronization
block 500 in the form of two signals. Indeed, according to the
invention, the data is divided into two: a first part for the most
significant bits is received on a pair of wires and a second part
for the least significant bits is received on another pair of
wires.
[0172] Thus the synchronization block 500 gives each
de-serialization block a synchronization clock signal. It
determines it from the signal received and thus determines the
value of the signal for each of these periods.
[0173] The deserialization blocks 501a and 501b will parallelize
the data received, i.e. piece each of them on eight bits.
[0174] When the data is parallelized, it is transferred to the
segment reception blocks 502b for the segments containing the most
significant bits and 502a for the segments containing the least
significant bits.
[0175] These blocks 502a and 502b will rebuild the segments
received and furthermore verify that the received segment is
correct by carrying out, for example, a classic parity check on the
received data. This check is known to those skilled in the art.
[0176] When this check is made, the block 502b transfers the
reconstructed most significant segment to a FIFO type storage means
503b. It also generates an information signal, intended for the
FIFO control module 504, on the presence of a new segment.
[0177] The block 502a performs the same operations as the block
502b but does so for the segments containing the least significant
bits. This block shall not be described in greater detail.
[0178] The reception FIFO control module 504 informs the data
output control module 506 about the reception of the totality of a
segment, the segment comprising both least significant bytes stored
in the FIFO 503a (rx_fifo_LSB) and most significant bytes stored in
the FIFO 503b (rx_fifo_MSB).
[0179] The data output control module 506 informs the Int_FIFO
control module 410, described here above with reference to FIG. 4,
of the reception of a new segment.
[0180] The module 506 manages the insertion of the credit
characters by the modules 510a and 510b as a function of the read
operations on the storage means 503a and 503b,
[0181] The control module 410 can then make a read request to read
the data received through the modules for the analysis of the
credits 505a and 505b.
[0182] The credit analysis modules 505a and 505b respectively
extract, firstly, the information representing the FIFO memory or
destination buffer (input FIFO 404a to 404c), secondly, the
information representing a release of credit in a FIFO memory or
remote reception buffer.
[0183] In a first alternative mode of implementation, the
information representing the destination buffer or else the
information representing a release of credit is determined from a
control character inserted in the data field of the segment.
[0184] In a second alternative mode of implementation, the
information representing the destination buffer or else the
information representing a release of credit is determined from a
predetermined field in the segment.
[0185] When the credit analysis modules 505a and 505b respectively
identify a destination buffer, the information is transmitted
through a control signal to the control module of Int_FIFO 410 so
that this control module will select the input FIFO (404a to 404c)
to which the data will be transferred.
[0186] When the credit analysis modules 505a and 505b respectively
identify a credit release, the information is transmitted through a
control signal to the data-sending module 512.
[0187] The data-sending module 512, manages the method of
segmentation for the transmission of the packets from each of the
output FIFOs (403a to 403c). The transfer of data from one of the
output FIFOs (403a to 403c) firstly towards the FIFO for sending
the most significant bytes 511a (tx_FlFO_MSB) and secondly to the
FIFO for sending the least significant bytes 511b (tx_FIFO_LSB) is
done through the credit insertion modules 510a for the least
significant values and 510b for the most significant values.
[0188] Firstly, through control signals, the data-sending modules
512 receive credit release information coming from the credit
analysis module 505a and 505b respectively.
[0189] Secondly, the data-sending module 512 receives read requests
from the output FIFOs (403a to 403c) coming from the control module
of Int_FIFO 410. The state machine describing the working of the
data-sending module 512 shall be described further below with
reference to FIG. 9.
[0190] Furthermore, the control module Int_FIFO 410 notifies the
credit insertion module 510, when a predetermined number of pieces
of data has been read in one of the input FIFOs (404a to 404c). The
credit insertion modules 510a, and 510b respectively then insert a
piece of information, into the segment, representing a release of
credit associated with one of the input FIFOs (404a to 404c).
[0191] In an alternative mode of implementation, the information
representing a release of credit is determined from a control
character inserted into the data field of the segment described
here below with reference to FIG. 8.
[0192] In another alternative mode of implementation, the
information representing a release of credit is determined from a
predetermined field in the segment: this shall be d here below with
reference to FIG. 8.
[0193] The FIFO sending control module 513 notifies the
data-sending module 512 of the sending of the totality of a
segment, the segment comprising both the least significant bytes
stored in the FIFO 511b (tx_FIFO_LSB) and the most significant
bytes stored in the FIFO 511a (tx_FIFO_MSB).
[0194] The blocks 514a and 514b will carry out the transmission of
the segments by computing the parity control field associated with
the segment. They therefore inform the FIFO sending control module
513 of the end of transmission of each part of the (respectively
least significant and most significant) segment.
[0195] The blocks 515a and 515b will make byte-by-byte transmission
of each segment in the form of a binary string through the sending
synchronization block 516. The sending synchronization block 516 is
chiefly in charge of generating a synchronization signal at the
head of a segment.
[0196] FIG. 6 shows the physical interface module 550 connecting
each Y link interface 203 and a transmission medium 160a, 160b,
160c and 160d respectively, in the present case a CAT5 type cable
consisting of four pairs of twisted wires.
[0197] This physical interface module 550 is placed, for example,
in a switching means 150a located in the central switching unit
160.
[0198] This interface module comprises a set of transformers
referenced 606 to 609 which provide the galvanic insulation between
the CAT5 cable and the reception synchronization block 500 and
transmission synchronization block 516 described with reference to
FIG. 5.
[0199] These transformers have a midpoint and are, for example,
H2006A models commercially distributed by the firm Pulse.
[0200] Two transformers are dedicated to the transmission of
information such as that described with reference to FIG. 8. These
are for example, the transformers 608 and 609. Two transformers are
dedicated to the reception of information such as that described
with reference to FIG. 8. In this case, these are the transformers
606 and 607.
[0201] The transformers 606 and 607 are connected to the reception
synchronization block 500 described in FIG. 5, the transformers 608
and 609 are connected to the sending synchronization block 516
described in FIG. 5.
[0202] The midpoints of the transformers 608 and 609 are connected
to a classic DC supply, for example a power supply of about 48
volts.
[0203] The midpoints of the transformers 606 and 607 are connected
to the public telephone network by means of a connection 611.
[0204] An RJ45 type connection means 610 connects the interface
module to the CAT5 cable.
[0205] FIG. 7 represents the physical interface module 550
connecting the Y link interface of each of the multimedia interface
devices 150a, 150b, 150c and 150d and the transmission medium 160a,
160b, 160c and 160d which, in the present case, are CAT5 consisting
of four pairs of twisted wires.
[0206] The physical interface module 550 is placed, for example, in
a switching means 150a which is itself placed, according to one
variant, in a wall socket.
[0207] This interface module 550 comprises a set of transformers
referenced 706 to 709 which provide the galvanic insulation between
the CAT5 cable and the reception synchronization block 500 and
transmission synchronization block 516.
[0208] These transformers comprise a midpoint and are, for example,
H2006A models commercially distributed by the firm Pulse.
[0209] Two transformers are dedicated to the transmission of
information such as that described with reference to FIG. 8. These
are, for example, the transformers 706 and 707. Two transformers
are dedicated to the reception of information such as that
described with reference to FIG. 8. In this case, these are the
transformers 708 and 709.
[0210] The transformers 708 and 709 are connected to the reception
synchronization block 500 described in FIG. 5, the transformers 706
and 707 are connected to the sending synchronization block 516
described in FIG. 5.
[0211] The midpoints of the transformers 708 and 709 are connected
to a classic voltage converter referenced 715. Owing to the
characteristics of the CAT5 cable, which is formed by 24 AWG type
conductors, the series resistance is about 20 ohm per hectometer
for a pair of conductors.
[0212] In a particular case of the present invention, the power
supply source will be of the order of 48 volts, and the voltage
converter must be capable of giving a minimum power of 14
watts.
[0213] This energy is then distributed among the different
components of the interface device 150a.
[0214] The midpoints of the transformers 706 and 707 are connected,
by means of an RJ11 type connector 711, to a telephone set or any
other device capable of communicating on a public telephone network
such as a modem.
[0215] An RJ45 type connection means 710 connects the interface
module to the CAT5 cable.
[0216] Thus, one and the same cable will take traffic of
information coming from information sources according to the IEEE
1394 standard, Ethernet type information, audio/video information
coming from analog devices such as videocassette recorders, this
information traveling bi-directionally on two transmission pairs
and two reception pairs. This cable will also take a telephone line
and the electrical power supply of the multimedia interface
device.
[0217] The telephone line uses the technique known as the "ghost
pairs" technique on two pairs of twisted wires. The electrical
power supply to the multimedia interface device uses the two
remaining pairs in the same way.
[0218] As a variant, two distinct telephone lines may also be
allocated, and the multimedia device can then be powered in another
way, for example by a battery or by connection to the home
electrical network provided that it is appropriately adapted.
[0219] As a variant, two power supplies may also be allocated, one
replacing the telephone line. This makes it possible to furnish two
different voltage power supplies or higher electrical power.
[0220] FIG. 8 describes the structure of the data segments
transmitted on the cable 160a for example, to a switching device
250a , 250b and 250c.
[0221] A segment is constituted by an entity, not shown in the
figure, comprising at least information needed for the
synchronization of the synchronization bloc of the receiver.
[0222] The segment then comprises a field of data referenced 801 to
806. The fields 808 and 809 are controlled fields of the segment.
The sending of a segment is distributed among two independent pairs
as mentioned with reference to FIG. 5. The field 801 comprises
information representing the address of the FIFO type storage means
contained in the audio/video network module for which the data
contained in the field 802 is intended. This address corresponds
for example to a code associated with the FIFO memory 404a
described with reference to FIG. 4.
[0223] The fields 803 and 805 also comprise a code respectively
associated with the FIFO memories 404b and 404c of FIG. 4.
[0224] The fields 804 and 806 comprise data intended respectively
for the FIFO memories 404b and 404c of FIG. 4.
[0225] The field 808 encoded on eight bits is a field reserved for
the insertion of information for the verification of the conformity
of the data at the reception block segment 502a described with
reference to FIG. 5.
[0226] In a classic way known to those skilled in the art, the bits
of the segment at a predetermined level are counted and the counted
number modulo 256 is inserted into this field.
[0227] At the receiver, this same counting of the bits of the
segment is done. A simple comparison of the counted value with the
value contained in the field 808 makes it possible to detect the
presence or absence of error in the transmission.
[0228] According to one embodiment, the last field 809 contains
information representing the quantity of recently released
information, more specifically the credits in the storage means
404a to 404c.
[0229] This field is sub-divided into four sub-fields, and each of
the sub-fields is encoded on two bits.
[0230] Each of the sub-fields 810, 811, and 812 is respectively
associated with a storage means 404a, 404b and 404c of FIG. 4.
[0231] The following are the contents and meaning of these
sub-fields: [0232] 00: no credit sent, [0233] 01: one credit sent,
[0234] 10: two credits sent, [0235] 11: three credits sent.
[0236] The sub-field 810 indicates the credit pertaining to the
storage means 404a, the sub-field 811 indicates the credit
pertaining to the storage means 404b, the sub-field 812 indicates
the credit pertaining to the storage means 404c, An additional
sub-field 813 may be associated with an additional storage
means.
[0237] According to another embodiment, the field 809 as well as
the sub-fields 810, 811, 812 and 813 are not included in the
segment.
[0238] Control characters are inserted into the fields 802, 804 and
806.
[0239] Table 1 describes the values of the different control
characters as well as their meaning. TABLE-US-00001 TABLE 1 Credit
0 0xF01F Available credit towards FIFO 404a Credit 1 0xF027
Available credit towards FIFO 404b 2 0xF033 Available credit
towards FIFO 404c
[0240] FIG. 9 describes the state machine associated with the
data-sending module 512.
[0241] The data-sending module 512 can be in three possible states
numbered 900 to 902 as a function of different events referenced
910 to 913.
[0242] This module awaits an event in the "idle" state 900.
[0243] In this state, two types of events may appear and effect a
change in the state data-sending module. The first event referenced
910 consists of the reception, by the data-sending module 512, of
credit release information coming from the credit analysis module
505. The second event referenced 912 consists of the reception, by
the data-sending module 512 of read requests for reading at least
one of the FIFOs 403a to 403c of FIG. 4. The change in state
following the second event is conditional on the fact that the
credit associated with the concerned FIFO is not zero.
[0244] On the reception of the first event 910, the data-sending
module 512 goes into the "credit received" state referenced 901.
When the event 911 consisting of the incrementation of the received
credit takes place, the data-sending module returns to the state
900 described here above.
[0245] If, in the state 900, the data-sending module 512 receives
an event such as the second event referenced 912 described here
above, consisting of the reception, by the data-sending module 512,
of read requests made by the control module Int_FIFO 410 for
reading at least one of the FIFOs 403a to 403c and if the credit
associated with the concerned FIFO is not zero, then the
data-sending module goes to the step 902.
[0246] The data-sending module 512 will remain in the state 902 so
long as the event 913 has not occurred.
[0247] This event consists of the transfer of a predetermined
number of pieces of data from the FIFO at which the sending module
has received a read request to the storage means 510a and 510b,
511a and 511b through the respective credit insertion modules 510a
and 510b.
[0248] The event 913 also consists of a piece of information on
decrementating of credit associated with the FIFO concerned.
[0249] At the occurrence of the event 913, the data-sending module
goes back to the step 900.
[0250] FIG. 10 shows a second variant of the physical module
interface connecting the Y link interface and the transmission
medium in the switching device.
[0251] In general, the physical interface modules are identical to
the physical interface modules as described with reference to FIGS.
6 and 7 apart from the fact that the telephone link is no longer
given by means of "ghost pairs" but through a combination of
low-pass filters and bandpass filters.
[0252] The transformers 606 to 609 are identical to those described
with reference to FIG. 6 and shall therefore not be described.
[0253] The transformers 706 to 709 are identical to those described
with reference to FIG. 7 and shall therefore not be described.
[0254] The connectors 610 to 611 are identical to those described
with reference to FIG. 6 and shall therefore not be described.
[0255] The connectors 710 to 711 are identical to those described
with reference to FIG. 7 and shall therefore not be described.
[0256] The supply of electrical power to the multimedia interface
device as described with reference to FIGS. 6 and 7 is not shown in
FIG. 10 for the sake of simplicity but may of course form part of
this second variant.
[0257] In this variant, the multimedia interface device as well as
the switching device comprise filtering means to filter signals
coming from a telephone communications device, for example a
telephone set connected to the unique cable pair constituting at
least one pair.
[0258] A first filter 612 is placed between the secondary winding
of the transformer 606 and the connector 610. The filter 612 is a
bandpass filter and its function is to eliminate the signal
associated with the telephone communication using the same twisted
pair as the one connected to the secondary winding of the
transformer 606. However, this same filter allows the data
compliant with the data shown with reference to FIG. 8 to flow
towards the secondary winding of the transformer 606.
[0259] This filter has a low cut-off frequency of about 350 Khz.
With this cut-off frequency, the frequencies present on the
telephone line are sufficiently attenuated to prevent any problem
on the data
[0260] It must be noted that this same cut-off frequency is
compatible with the frequency spectrum of the data flowing on the
twisted pair. This filter 612 is constituted by four capacitors
referenced 1110, 1111, 1113 and 1114 in FIG. 11b and having a value
of about 2.2 nanofarads. This filter also comprises an inductor
referenced 1112, with an inductance of 100 microhenries.
[0261] The capacitors 1110 and 1113 are connected to the secondary
winding of the transformer 606 and the capacitors 1111 and 1114 are
connected to the connector 610.
[0262] The filter 712 placed at the multimedia interface device is
identical to the filter 612 and shall therefore not be described in
greater detail.
[0263] A secondary filter referenced 614 is placed between the
secondary winding of the transformer 606 and the connector 611
enabling the link with the public telephone network. The filter 614
is a low-pass filter and its function is to eliminate the data
compliant with that shown with reference to FIG. 8 and using the
same twisted pair as the telephone. However, this same filter
allows the telephone signal to flow towards the connector 611.
[0264] This filter has a cut-off frequency of about 20 Khz. With
this cut-off frequency, the frequencies present on the telephone
line are not attenuated.
[0265] The filter 614 described in FIG. 11a is formed by a set of
three capacitor referenced 1100, 1102 and 1105 and three inductors
referenced 1101, 1103 and 1105.
[0266] The inductors 1101 and 1104 have a value of about one
millihenry and the value of the inductor 1103 is about one
microhenry.
[0267] The capacitors 1100 and 1105 have a value of about one
picofarad and the inductor 1102 has a value of about 470
picohenry.
[0268] The link connecting the capacitor 1100 and the capacitor
1102 as well as the link connecting the capacitor 1104 and the
inductor 1003 are respectively connected to the connector 611.
[0269] The link connecting the capacitor 1100 and the capacitor
1101 as well as the link connecting the capacitor 1104 and the
inductor 1005 are respectively connected to the connector 610.
[0270] The filter 714 placed at the level of the multimedia
interface device is identical to the filter 614, and shall
therefore not be described in greater detail.
[0271] It must be noted that the filters described are
non-restrictive examples. Those skilled in the art will be able, in
a classic way, to use other filters in seeing to it that their
input impedance values have transmission poles so as not the
attenuate the signal.
[0272] Higher-order filters or even active filters could, of
course, be used.
[0273] Naturally, the present invention is not limited to the
details of the exemplary embodiments described herein but can be
extended, on the contrary, to modifications within the scope of
those skilled in the art, without departing from the framework of
the invention.
* * * * *