U.S. patent application number 13/093188 was filed with the patent office on 2011-09-08 for packet communication system.
This patent application is currently assigned to HITACHI, LTD.. Invention is credited to Toshiaki Koyama.
Application Number | 20110216764 13/093188 |
Document ID | / |
Family ID | 14221595 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110216764 |
Kind Code |
A1 |
Koyama; Toshiaki |
September 8, 2011 |
PACKET COMMUNICATION SYSTEM
Abstract
The packet communication system enables communication between a
communication unit connected in a conventional telephone network
and a communication unit in a packet communication network. A
device for exclusively selecting the connection network is provided
so that, at the time of transmission of a signal from one
communication unit to another, the connection path is selected
according to the kind of the network to which the other
communication unit belongs. At the time of signal reception, the
communication unit is connected to only one of the conventional
telephone network and the packet communication network. The packet
communication system includes a packet processor for converting an
information signal, such as speech, inputted from an input unit
(for example, a transmitter microphone of a handset) into the form
of a packet
Inventors: |
Koyama; Toshiaki; (Zama-shi,
JP) |
Assignee: |
HITACHI, LTD.
Tokyo
JP
|
Family ID: |
14221595 |
Appl. No.: |
13/093188 |
Filed: |
April 25, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11210804 |
Aug 25, 2005 |
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13093188 |
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10396824 |
Mar 26, 2003 |
7139265 |
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11210804 |
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09238160 |
Jan 28, 1999 |
6563815 |
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10396824 |
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08827054 |
Mar 26, 1997 |
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09238160 |
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08436183 |
May 9, 1995 |
5654957 |
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08827054 |
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Current U.S.
Class: |
370/352 |
Current CPC
Class: |
H04L 2012/6481 20130101;
H04M 3/533 20130101; H04M 7/006 20130101; H04M 7/0069 20130101;
H04M 3/42323 20130101; H04M 7/0057 20130101; H04M 3/428 20130101;
H04M 7/12 20130101; H04M 1/2535 20130101; H04L 12/6418
20130101 |
Class at
Publication: |
370/352 |
International
Class: |
H04L 12/66 20060101
H04L012/66 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 1994 |
JP |
06-098508 |
Claims
1. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said packet
processor receives the packet data transmitted from a transmission
source coupled to said packet communication network, thereafter
said telephone controller receives a signal transmitted from a
transmission source coupled to said telephone network, and said
telephone controller produces a busy tone signal to be transmitted
to said telephone network.
2. A voice communication apparatus according to claim 1: Wherein
said signal transmitted from a transmission source coupled to said
telephone network is rejected.
3. A voice communication apparatus according to claim 2: wherein
said busy tone signal is transmitted to said telephone network.
4. A voice communication apparatus according to claim 3: wherein
said controller controls said switch and connects said voice input
and output unit to said packet processor.
5. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said packet
processor receives the packet data transmitted from a transmission
source coupled to said packet communication network, thereafter
said telephone controller receives a signal transmitted from a
transmission source coupled to said telephone network, and said
signal transmitted from a transmission source coupled to said
telephone network is rejected.
6. A voice communication apparatus according to claim 5: wherein
said telephone controller produces a busy tone signal to be
transmitted to said telephone network.
7. A voice communication apparatus according to claim 6: wherein
said busy tone signal is transmitted to said telephone network.
8. A voice communication apparatus according to claim 7: wherein
said controller controls said switch and connects said voice input
and output unit to said packet processor.
9. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said packet
processor receives the packet data transmitted via said packet
communication network, thereafter said telephone controller
receives a signal transmitted via said telephone network, and said
telephone controller produces a busy tone signal to be transmitted
to said telephone network.
10. A voice communication apparatus according to claim 9: wherein
said signal transmitted via said telephone network is rejected.
11. A voice communication apparatus according to claim 10: wherein
said busy tone signal is transmitted to said telephone network.
12. A voice communication apparatus according to claim 11: wherein
said controller controls said switch and connects said voice input
and output unit to said packet processor.
13. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said packet
processor receives the packet data transmitted via said packet
communication network, thereafter said telephone controller
receives a signal transmitted via said telephone network, and said
signal transmitted via said telephone network is rejected.
14. A voice communication apparatus according to claim 13: wherein
said telephone controller produces a busy tone signal to be
transmitted to said telephone network.
15. A voice communication apparatus according to claim 14: wherein
said busy tone signal is transmitted to said telephone network.
16. A voice communication apparatus according to claim 15: wherein
said controller controls said switch and connects said voice input
and output unit to said packet processor.
17. A program stored in a non-transitory computer readable medium
adapted to perform the following processes: receiving the packet
data transmitted via a packet communication network, receiving a
signal transmitted via a telephone network thereafter, producing a
busy tone signal to be transmitted to said telephone network.
18. A program stored in a non-transitory computer readable medium
according to claim 17, further adapted to perform the following
process: rejecting said signal transmitted from a transmission
source coupled to said telephone network.
19. A program stored in a non-transitory computer readable medium
according to claim 18, further adapted to perform the following
process: transmitting said busy tone signal to said telephone
network.
20. A program stored in a non-transitory computer readable medium
adapted to perform the following processes: receiving the packet
data transmitted via a packet communication network, receiving a
signal transmitted via a telephone network thereafter, and
rejecting said signal transmitted from a transmission source
coupled to said telephone network.
21. A program stored in a non-transitory computer readable medium
according to claim 20, further adapted to perform the following
process: producing a busy tone signal to be transmitted to said
telephone network.
22. A program stored in a non-transitory computer readable medium
according to claim 21, further adapted to perform the following
process: transmitting said busy tone signal to said telephone
network.
23. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said telephone
controller receives a signal transmitted from a transmission source
coupled to said telephone network, thereafter said packet processor
receives a packet data transmitted from a transmission source
coupled to said packet communication network, and said packet
processor produces a packet data indicating busy status to be
transmitted to said packet communication network.
24. A voice communication apparatus according to claim 23: wherein
said packet data transmitted from a transmission source coupled to
said packet communication network is rejected.
25. A voice communication apparatus according to claim 24: wherein
said packet data indicating busy status is transmitted to said
packet communication network.
26. A voice communication apparatus according to claim 25: wherein
said controller controls said switch and connect said voice input
and output unit to said telephone controller.
27. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said telephone
controller receives a signal transmitted from a transmission source
coupled to said telephone network, thereafter said packet processor
receives a packet data transmitted from a transmission source
coupled to said packet communication network, and said packet data
transmitted from a transmission source coupled to said packet
communication network is rejected.
28. A voice communication apparatus according to claim 27: wherein
said packet processor produces a packet data indicating busy status
to be transmitted to said packet communication network.
29. A voice communication apparatus according to claim 28: wherein
said packet data indicating busy status is transmitted to said
packet communication network.
30. A voice communication apparatus according to claim 29: wherein
said controller controls said switch and connects said voice input
and output unit to said telephone controller.
31. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said telephone
controller receives a signal transmitted via said telephone
network, thereafter said packet processor receives a packet data
transmitted via said packet communication network, and said packet
processor produces a packet data indicating busy status to be
transmitted to said packet communication network.
32. A voice communication apparatus according to claim 31: wherein
said packet data transmitted via said packet communication network
is rejected.
33. A voice communication apparatus according to claim 32: wherein
said packet data indicating busy status is transmitted to said
packet communication network.
34. A voice communication apparatus according to claim 33: wherein
said controller controls said switch and connects said voice input
and output unit to said telephone controller.
35. A voice communication apparatus, comprising: a packet processor
coupled to a packet communication network, said packet processor
converting a voice signal from/to a packet data bilaterally to
enable communication of the packet data to said packet
communication network; a telephone controller coupled to a
telephone network to enable communication of the voice signal on
said telephone network; a switch connected with a voice input and
output unit and which connects said packet processor or said
telephone controller with said voice input and output unit; and a
controller connected with said switch, wherein said telephone
controller receives a signal transmitted via said telephone
network, thereafter said packet processor receives a packet data
transmitted via said packet communication network, and said packet
data transmitted via said packet communication network is
rejected.
36. A voice communication apparatus according to claim 35: wherein
said packet processor produces a packet data indicating busy status
to be transmitted to said packet communication network.
37. A voice communication apparatus according to claim 36: wherein
said packet data indicating busy status is transmitted to said
packet communication network.
38. A voice communication apparatus according to claim 37: wherein
said controller controls said switch and connects said voice input
and output unit to said telephone controller.
39. A program stored in a non-transitory computer readable medium
adapted to perform the following processes: receiving a signal
transmitted via said telephone network, said packet receiving a
packet data transmitted via said packet communication network
thereafter, and producing a packet data indicating busy status to
be transmitted to said packet communication network.
40. A program stored in a non-transitory computer readable medium
according to claim 39, further adapted to perform the following
process: rejecting said packet data transmitted via said packet
communication network.
41. A program stored in a non-transitory computer readable medium
according to claim 40, further adapted to perform the following
process: transmitting said packet data indicating busy status to
said packet communication network.
42. A program stored in a non-transitory computer readable medium
adapted to perform following processes: receiving a signal
transmitted via said telephone network, and receiving a packet data
transmitted via said packet communication network thereafter,
rejecting said packet data transmitted via said packet
communication network.
43. A program stored in a non-transitory computer readable medium
according to claim 42, further adapted to perform the following
process: producing a packet data indicating busy status to be
transmitted to said packet communication network.
44. A program stored in a non-transitory computer readable medium
according to claim 43, further adapted to perform the following
process: transmitting said packet data indicating busy status to
said packet communication network.
Description
[0001] This is a continuation application of U.S. Ser. No.
11/210,804, filed Aug. 25, 2005, which is a continuation
application of U.S. Ser. No. 10/396,824, filed Mar. 26, 2003 (now
U.S. Pat. No. 7,139,265); which is a continuation application of
U.S. Ser. No. 09/238,160, filed Jan. 28, 1999 (now U.S. Pat. No.
6,563,815); which is a continuation application of U.S. Ser. No.
08/827,054, filed Mar. 26, 1997 (now abandoned); which is a
continuation application of U.S. Ser. No. 08/436,183, filed May 9,
1995 (now U.S. Pat. No. 5,654,957).
[0002] This application claims priority to JP 06-098508, filed May
12, 1994.
BACKGROUND OF THE INVENTION
[0003] This invention relates to a packet communication system used
for packet mode communication of a signal, such as, an audio signal
or a video signal through a communication network, and more
particularly to a packet communication system suitable for packet
mode communication of a signal, such as, a speech signal between
communication networks using signal types different from each
other.
[0004] With the recent progress of the architecture of a LAN (local
area network), the network system connecting small size computers,
such as, personal computers using the LAN is also increasing. Thus,
an attempt is now being made for integration of communications by
permitting voice communication on the LAN in addition to a
conventional telephone network (including a PBX network that is a
private branch exchange network).
[0005] As an example of such an attempt, there is a "voice
communication system" as shown in FIG. 4. This voice communication
system is composed of telephones connected to a convention
telephone network, packet communication units connected to a
packeted speech signal communication network (referred to
hereinafter as a packet communication network), and a communication
gateway used to realize mutual connections between the telephones
and the packet communication units. A network carrying such a
speech packet on the LAN described above is an example of the
packet communication network.
[0006] Referring to FIG. 4, the reference numerals 21 and 22
designate telephones connected to a private branch exchange network
(a PBX network) 13 and a public telephone network 20, 104
designates a subscriber line of the private branch exchange network
13, 105 designates a subscriber line of the public telephone
network 20, and they have the same interface. On the other hand,
the reference numeral 101 designates a packeted speech signal
transmission network in the form of, for example, a LAN based on
the CSMA/CD (carrier sense multiple access with collision
detection) scheme according to the standards defined in the IEEE
802.3. A plurality of packet communication units 14, 15 and 16 are
connected to this LAN 101.
[0007] The packet communication units 14, 15 and 16 are in the form
of small size computers, such as, personal computers provided with
handsets 17, 18 and 19 respectively. These packet communication
units 14, 15 and 16 have, on one hand, functions of packeting
speech signal inputs from the handsets 17 to 19 and sending out the
packeted speech signals onto the LAN 101 and, on the other hand,
functions of converting the packeted speech signals received via
the LAN 101 into ordinary voice streams again and reproducing the
original speech by the handsets 17, 18 and 19.
[0008] The reference numeral 11 designates a mail box connected to
the LAN 101 to store a filed voice mail. The packet communication
units 14, 15 and 16 can store such filed voice mails in the mail
box 11 through the LAN 101 and can also fetch such voice mails,
transmitted from the other packet communication units and stored in
the mail box 11, so as to internally convert the stored voice mails
into voice streams again and reproduce the original speech signals
by the handsets 17, 18 and 19.
[0009] The reference numeral 12 designates a communication gateway
which controls communication between the LAN 101 that is the packet
communication network and the private branch exchange network 13
that is the conventional telephone network. In this case, a
subscriber line accommodating an existing telephone is commonly
used as a connection line 102 between the private branch exchange
network 13 and the communication gateway 12. However, this
connection line 102 may be an interface between the telephones in
the private branch exchange network.
[0010] Suppose now the case where voice communication is made among
the packet communication units 14, 15 and 16 in the LAN 101 in the
voice communication system having the structure described above. In
the case of making voice communication between, for example, the
packet communication units 14 and 16, the speech packet is
transferred through a communication path 121. On the other hand, in
the case of making communication between the packet communication
unit 14 and the private branch exchange network 13 or the telephone
21 or 22 connected to the public telephone network 20, the speech
packet is transmitted through a communication path 122 in the LAN
101. In this case, the packeted speech signal on the LAN 101 is
converted by the communication gateway 12 into the corresponding
voice stream before being transferred to the private branch
exchange network 13 or the public telephone network 20. In the case
of a speech signal transmitted from the side of the private branch
exchange network 13 or the public telephone network 20 toward the
packet communication unit 14 in the LAN 101, its voice stream is
packeted by the communication gateway 12 to be sent out to the LAN
101.
[0011] In the case of integration of voice communication in a
packet communication network in the form including a conventional
telephone network, it is an undeniable fact that the number of
users having their telephones connected to the conventional
telephone network is actually predominantly large although the
number of terminals connected to the packet communication network
is increasing. Therefore, when the desired integration of the voice
communication is considered, the amount of communication between
the telephones connected to the conventional telephone network and
the terminals connected to the packet communication network is
expected to considerably increase.
[0012] On the other hand, when the future of the packet
communication network is reviewed, an undeniable situation will
appear in which the users possessing their telephones already
become new members of the packet communication network. For
example, although specific users, such as, persons holding
administrative positions in a company only possess the packet
communication units in the LAN in the company at present, it is
apparent that there will be an increasing tendency of introducing
the packet communication units in future so that all the members of
the company can possess the packet communication units.
[0013] However, the prior art packet communication units connected
in the packet communication network are basically considered to
make communication in packet form. Thus, the desired integration of
the voice communication in the form including the conventional
telephone network will bring forth such a problem that the
communication gateway tends to be overloaded due to concentration
of loads, resulting in impossibility of connection or
communication.
[0014] Further, when the packet communication unit is newly
provided for the user possessing his telephone already, the same
user possesses both the telephone and the packet communication
unit. As a result, the cost inevitably increases, and such a
problem arises that the user cannot deal with simultaneous
occurrence of a communication request from both the telephone and
the packet communication unit. The same applies also to the case
where the telephone is newly provided for the user who possesses
the packet communication unit only.
SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to provide a packet
communication system which can reliably and economically ensure
communication between communication units connected in a
conventional telephone network and those connected in a packet
communication network.
[0016] Another object of the present invention is to provide a
packet communication system which is constructed to be accommodated
in the prior art network by adding a function of connection to the
conventional telephone network in addition to the function of
connection to the packet communication network, so as to lighten
loads imposed on a communication gateway, to decrease the amount of
materials of an interface circuit or parts for connection to the
conventional telephone network, and to reduce the cost of the
system.
[0017] Still another object of the present invention is to provide
a packet communication system in which a user possessing his
telephone already can transmit speech through his telephone
subscriber line possessed already and which also makes it possible
to make voice communication with another packet communication unit
connected in the packet communication network.
[0018] Yet another object of the present invention is to provide a
packet communication system which, when an incoming call arrives at
the user's packet communication unit from another while the user is
talking, displays the arrival of the incoming call on a display, so
that such a call can be dealt with while the other party does not
know the fact.
[0019] A further object of the present invention is to provide a
packet communication system in which a speech or like signal
arriving at the user's packet communication unit from the
conventional telephone network is turned into mail form without the
necessity for re-connection of the input to the communication
gateway, so as to shorten the period of time required for turning
the input into the mail form and also to lighten the load imposed
on the communication gateway.
[0020] A still further object of the present invention is to
provide a packet communication system in which, even in the event
of sudden power supply interruption, an output unit, such as, an
externally located telephone is used for communication, so that,
even when the exclusive user of the packet communication unit is
absent, and the power supply is not turned on, another person can
respond to the input.
[0021] The present invention which attains the above objects
provides a packet communication system making communication between
a communication unit connected in a conventional telephone network
and that in a packet communication network, in which a function of
connection to the conventional telephone network is added to a
function of connection to the packet communication network, and
means for exclusively selecting the connection network is provided
so that, at the time of transmission of a signal from one of the
communication units to the other, the connection path is selected
according to the kind of network to which the other communication
unit belongs, while, at the time of signal reception, the
communication unit is connected to only one of the conventional
telephone network and the packet communication network. That is,
the packet communication system comprises packet processor means
for converting a speech or like information signal inputted from an
input unit (for example, a transmitter microphone of a handset)
into the form of a packet to transmit the packet to the packet
communication network and converting the packet transmitted from
the packet communication network into the original speech or like
information signal stream to reproduce the signal stream by an
output unit (for example, a receiver of the handset), conventional
telephone network interface control means for reproducing the
speech or like information signal arrived from the conventional
telephone network by the output unit, and exclusive selection means
for exclusively selecting only one of the conventional telephone
network and the packet communication network in response to the
arrival of the input signal.
[0022] Thus, in the case of communication between the communication
unit connected in the packet communication network and the
communication unit, such as, the telephone connected in the
conventional telephone network, a connection path is formed between
them by the function of connection to the conventional telephone
network. On the other hand, in the case of communication between
the communication units in the packet communication network, a
communication path is formed between them by the function of
connection to the packet communication network. Therefore, the
communication gateway is utilized only for the communication
between the communication unit (for example, the telephone)
connected to the conventional telephone network only and the
communication unit connected to the packet communication network
only, and concentration of loads on the communication gateway is
avoided. Thus, even when the number of the communication units
connected in the conventional telephone network may be large,
information, such as, audio information and/or video information
can be reliably communicated between the communication units in the
conventional telephone network and those in the packet
communication network.
[0023] Further, when the packet communication unit is newly
provided for the user possessing his telephone already connected to
the conventional telephone network, the sole requirement is to
connect the subscriber telephone line to the packet communication
system of the present invention, so that the telephone can be
eliminated, and communication of information, such as, audio
information and/or video information can be economically attained.
When, in this case, information signals are simultaneously inputted
from the communication unit connected in the packet communication
network and that in the conventional telephone network, only one of
the input signals is connected to the user's communication unit,
and a busy tone is issued for the other input signal, so that the
user does not feel any difficulty in dealing with such a
situation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] These and other objects, and features of the present
invention will become apparent from the following detailed
description of preferred embodiments of the present invention when
read in conjunction with the drawings:
[0025] FIG. 1 shows the system structure of an embodiment of the
packet communication system using the packet communication unit
according to the present invention.
[0026] FIG. 2 is a block diagram showing in detail the structure of
the packet communication unit used in the illustrated embodiment of
the present invention.
[0027] FIGS. 3A and 3B show the structure of the packet
communication unit provided with a connection switching circuit for
switching over connection with an externally located telephone in
the event of power supply interruption.
[0028] FIG. 4 shows the structure of one form of a prior art packet
communication system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Preferred embodiments of the present invention will now be
described in detail by reference to the drawings.
[0030] FIG. 1 shows the system structure of an embodiment of the
packet communication system using the packet communication unit
according to the present invention, and like reference numerals are
used in FIG. 1 to designate like parts appearing in FIG. 4.
Referring to FIG. 1, the reference numeral 30 designates a packet
communication unit having a function of connection both of a
conventional telephone network and a LAN 101 that is a packet
communication network. The packet communication unit 30 is provided
with a connection path for connection to the LAN 101 and a
connection interface line 103 for connection to a private branch
exchange network 13 that is the conventional telephone network. The
connection interface line 103 provides the same interface as that
for subscriber lines connected to telephones 21 and 22. The
connection interface line 103 may be connected to a public
telephone network 20 instead of the private branch exchange network
13. However, for the convenience of description, it is supposed
herein that the connection interface line 103 is connected to the
private branch exchange network 12.
[0031] FIG. 2 shows in detail the structure of the packet
communication unit 30. The packet communication unit 30 is composed
of a processor part 31 executing overall control, a display part 32
displaying various kinds of messages, for example, arrived
messages, scenes, for example, address input scenes, etc., viewed
by the user for the selection of the other party, a keyboard/mouse
part 35 inputting information required for operation, a speech
packet processor part 33 processing a speech input and a speech
output to and from a handset 19 so as to transmit and receive a
speech packet to and from the LAN 101, a telephone interface
control part 34 controlling the subscriber line interface of the
conventional telephone network, and a switch part 36 switched over
to select whether the speech stream to the handset 19 is to be
supplied from the side of the LAN 101 or from the side of the
private branch exchange network 13 therefor. These parts are
interconnected with each other by a bus 301.
[0032] In response to the signal arrival information supplied from
the speech packet processor part 33 or from the telephone interface
control part 34, the processor part 31 decides whether the
communication unit of the other party is connected to the LAN 101
or to the private branch exchange network 13 and executes
processing (for example, the exclusive control of the switch part
36) according to the result of decision. At the same time,
according to the network to which the communication unit of the
other party transmitting the signal is connected, the processor
part 31 instructs the speech packet processor part 33 or the
existing telephone interface control part 34 to originate a call.
Also, the processor part 31 controls the switch part 36 to control
the speech stream to be connected to the handset 19.
[0033] The packet communication unit 30 incorporated in this
embodiment uses a communication path 121 when it communicates with,
for example, a packet communication unit 14 located on the LAN 101,
while it uses another communication path 123 when it communicates
with the telephones 21 and 22 connected to the conventional
telephone network. Whether the communication unit of the other
party is located on the LAN 101 or connected to the private branch
exchange network 13 is decided on the basis of whether an
identifier specifying the communication unit of the other party is
a network address or a telephone number. Then, on the basis of the
result of decision, the packet communication unit 30 selects the
connection path.
[0034] When, for example, the communication unit of the other party
transmitting the call is the telephone 21, the processor part 31
identifies according to the telephone number that the communication
unit of the other party is connected in the private branch exchange
network 13, and the dial signal is generated from the telephone
interface control part 34. When, on the other hand, the
communication unit of the other party transmitting the signal is
the packet communication unit 14, the processor part 31 identifies
according to the network address that the communication unit of the
other party is located on the LAN 101, and the speech packet
processor part 33 transmits the packet including the address of the
other party. As this network address, the IP (internal protocol)
address, the host name of the packet communication unit or the like
is used. Whether the identifier used for specifying the unit
transmitting the signal is the telephone number or the network
address is decided on the basis of the rule for designating the
identifier of the unit to which the signal is transmitted. Further,
when it is so defined that the signal is transmitted through the
communication gateway 12 when the identifier of the unit to which
the signal is transmitted indicates the value in which the
identifier allocated to the communication gateway 12 is added to
the head of the telephone number, the packet communication unit 30
can communicate through the communication gateway 12 with the
telephones 21 and 22 connected to the conventional telephone
network. The network address or the telephone number of the
communication unit transmitting the signal is inputted from the
keyboard/mouse part 35 and displayed on the display part 32 of the
packet communication unit 30.
[0035] The packet communication unit 14 in the prior art packet
communication network must use the communication path 122 extending
through the communication gateway 12 when it makes communication
with the telephones 21 and 22 connected to the conventional
telephone network only, as shown in FIG. 4. The practical mode in
which the packet communication unit 30 is newly introduced to be
provided for the user who possesses the existing telephone already
will now be considered. In the case of the illustrated embodiment,
a bypass route in the form of the connection interface line 103
directly connecting the packet communication unit 30 and the
telephones 21 and 22 to the private branch exchange network 13 is
provided as shown in FIG. 1, so that the load imposed on the
communication gateway 12 can be greatly lightened.
[0036] The manner of exclusive control for the communication path
in the packet communication unit 30 will now be described. The
processor part 31 in the packet communication unit 30 can recognize
the state of both of the private branch exchange network 13 and the
LAN 101 through the speech packet processor part 33 or the
telephone interface control part 34. Therefore, when a speech
signal arrives while the packet communication unit 30 is making
communication, that signal is dealt with as in the case of usual
busy mode processing by the exclusive control function.
[0037] More concretely, when the packet communication unit 30
starts to make communication with the telephone 21 connected to the
private branch exchange network 13, the processor part 31 changes
over the switch part 36 to supply the speech input to the telephone
interface control part 34 and cuts off the supply of the speech
input from the speech packet processor part 33. When another speech
signal arrives from the other packet communication unit 14 under
the above situation, the processor part 31 generates a packet
indicating that the packet communication unit 30 is now busy, and
this packet is transmitted from the speech packet processor part 33
to the signal transmitting packet communication unit 14 through the
LAN 101.
[0038] On the other hand, when the packet communication unit 30
starts to make communication with the other packet communication
unit 14 connected to the LAN 101, the processor part 31 changes
over the switch part 36 to supply the speech input to the speech
packet processor part 33 and cuts off the supply of the speech
input from the telephone interface control part 34. When another
speech signal arrives from the telephone 21 connected to the
private branch exchange network 13 under the above situation, the
processor part 31 instructs the telephone interface control part 34
to generate a busy tone signal, and this signal is transmitted to
the signal transmitting telephone 21 through the connection
interface line 103 and the private branch exchange network 13.
[0039] The packet communication unit 30 operates to effect the
above manner of exclusive control for a speech signal that arrives
during communication, so that the user of the packet communication
unit 30 is required to respond to the signal arriving from one of
the networks only and is thus freed from such a situation in which
he is embarrassed with simultaneous arrival of speech signals from
both the networks. When a speech signal arrives during
communication by the packet communication unit 30, the processor
part 31 displays the arrival of the signal on the display part 32.
In this case, the switch part 36 may be changed over by the user
who viewed and confirmed the display on the display part 32.
[0040] The voice mail transfer function will now be described. When
a speech signal transmitted from, for example, the telephone 21 to
the packet communication unit 30 through the private branch
exchange network 13 is processed to be received as a speech mail
due to, for example, the absence of the user of the packet
communication unit 30, the speech signal received through the
connection interface line 103 is turned into the speech file by the
speech packet processor part 33 and is then transferred through the
LAN 101 to a mail box 11 to be stored as the mail whose destination
is the user's packet communication unit 30. Thus, as in the case of
an automatic answering telephone set, the speech signal arrived
during the period of absence of the user of the packet
communication unit 30 can be reproduced at any desired later time,
so that the processing required for turning the speech signal into
the speech mail via the communication gateway 12 is now
unnecessary, and the period of time required for the processing can
be shortened together with lightening of the load on the
communication gateway 12.
[0041] How to bypass the speech signal to an externally located
telephone in the event of interruption of the power supply to the
packet communication unit 30 will now be described by reference to
FIGS. 3A and 3B. In FIGS. 3A and 3B, the reference numeral 40
designates a packet communication unit exhibiting a bypass function
in the event of power supply interruption or down, 45 designates a
control part having a function similar to that of the packet
communication unit 30 shown in FIG. 2, 41 designates an externally
located telephone, and 42 designates a handset of the telephone 41.
The externally located telephone 41 has a power supply different
from that for the packet communication unit 40. The reference
numerals 43 and 44 designate relay contacts switched over under
control of the processor part 31 shown in FIG. 2. More concretely,
under the state in which the power supply for the packet
communication unit 40 is not turned on, the relay contact 44 is
switched over to the position where the connection interface line
103 is connected to the line terminal of the telephone 41 as shown
in FIG. 3A, while the relay contact 43 is switched over to the
position where the handset 42 is connected to the handset terminal
of the telephone 41.
[0042] On the other hand, under the state in which the power supply
for the packet communication unit 40 is turned on, the relay
contact 44 is switched over to the position where the connection
interface line 103 is connected to the line terminal of the
telephone interface control part 34 shown in FIG. 2 and included in
the control part 45 as shown in FIG. 3B, while the relay contact 43
is switched over to the position where the handset 42 is connected
to the handset terminal of the switch part 36 shown in FIG. 2 and
included in the control part 45.
[0043] By the above manner of bypass control, the externally
located telephone 41 can be used to secure the speech even in the
event of interruption of the power supply to the packet
communication unit 40. The function of the externally located
telephone 41 can be built in the packet communication unit 40 when
the circuit is designed to utilize the power fed from the telephone
exchange equipment.
[0044] The packet transmitted to and received from the LAN 101 in
the embodiments described above may be any one of a packet having a
variable length and that having a fixed length.
[0045] Although the above embodiments have been described by
reference to the case where a speech signal is transmitted and
received, it is apparent that the present invention is also
applicable to the case of transmission and reception of a video
signal or an image signal. Thus, a video telephone or the like can
be connected to the conventional telephone network. In the case of
transmission and reception of a video signal or an image signal,
the display part 32 functions as the output unit, while an image
input unit, such as, a television camera connected in place of the
transmitter microphone of the handset functions as the input
unit.
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