U.S. patent application number 11/276045 was filed with the patent office on 2006-06-29 for multiple channel optical tranceiver modules with compatibility features.
This patent application is currently assigned to CISCO TECHNOLOGY, INC.. Invention is credited to Matthew L. Heston, James II Theodoras.
Application Number | 20060140553 11/276045 |
Document ID | / |
Family ID | 35309508 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060140553 |
Kind Code |
A1 |
Theodoras; James II ; et
al. |
June 29, 2006 |
MULTIPLE CHANNEL OPTICAL TRANCEIVER MODULES WITH COMPATIBILITY
FEATURES
Abstract
Optical transceiver modules with multiple channel connection
with connectors on a motherboard of a line card for network
devices, such as a switch, router, crossconnect and the like, are
presented. The modules have staggered electronic boards which can
engage the connectors which are laterally displaced on the
motherboard. The connectors are also arranged so that one of them
can engage an optical transceiver module in an SFP connection so
that the motherboard connectors are compatible with multiple
channel and single channel (SFP) connections.
Inventors: |
Theodoras; James II; (Plano,
TX) ; Heston; Matthew L.; (Plano, TX) |
Correspondence
Address: |
AKA CHAN LLP / CISCO
900 LAFAYETTE STREET
SUITE 710
SANTA CLARA
CA
95050
US
|
Assignee: |
CISCO TECHNOLOGY, INC.
170 W. Tasman Drive
San Jose
CA
|
Family ID: |
35309508 |
Appl. No.: |
11/276045 |
Filed: |
February 10, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10847948 |
May 17, 2004 |
|
|
|
11276045 |
Feb 10, 2006 |
|
|
|
Current U.S.
Class: |
385/92 |
Current CPC
Class: |
H04B 10/691 20130101;
H05K 1/144 20130101; H04B 10/40 20130101 |
Class at
Publication: |
385/092 |
International
Class: |
G02B 6/36 20060101
G02B006/36 |
Claims
1. An optical transceiver module for removable mounting to a
motherboard, said optical transceiver module comprising: a housing
open at an end; a first electronic board fixed within said housing
and having an edge extending toward said open end of said housing;
a second electronic board fixed within said housing parallel to
said first electronic board and having an edge extending toward
said open end of said housing beyond said edge of first electronic
board; whereby upon mounting to said motherboard, said first and
second electronic boards of said optical transceiver module engage
first and second horizontally staggered connectors fixed to said
motherboard so as to make electrical connection with said first and
second connectors respectively.
2. The optical transceiver module of claim 1 wherein said first
electronic board carries signals of only one communication
channel.
3. The optical transceiver module of claim 2 wherein said first
electronic board and said first connector are disposed so as to
form an SFP connection therebetween.
4. The optical transceiver module of claim 3, wherein said second
electronic board carries signals of three communication
channels.
5. The optical transceiver module of claim 1 wherein said first
electronic board and said first connector are disposed so as to
form an SFP connection therebetween.
6. The optical transceiver module of claim 5, wherein said second
electronic board carries signals of three communication
channels.
7. The optical transceiver module of claim 1 wherein said first
electronic board carries signals on a plurality of pins at said
first electronic board edge, and said second electronic board
carries signals on a plurality of pins at said second electronic
board edge, said pluralities of pins of said first and second
electronic boards making electrical connections with said first and
second connectors respectively when said first and second
electronic boards engage said first and second horizontally
staggered connectors.
8. The optical transceiver module of claim 1 further comprising a
row of a plurality of optical emitters; and a row of a plurality of
optical detectors, said row of optical emitters is parallel to said
row of optical detectors, both said row of optical emitters and
said row of optical detectors both electrically coupled to said
first and second electronic boards.
9. The optical transceiver module of claim 8 wherein each optical
emitter and detector corresponds to an optical fiber retained in a
ferrule of a cable and the orientation of the row of optical
emitters and the row of optical detectors is such that light
reflected an angled surface of the ferrule at an aperture of an
optical fiber corresponding to an optical emitter is directed away
from an aperture of an optical fiber corresponding to an optical
detector.
10. The optical transceiver module of claim 8, wherein said row of
optical emitters comprises four laser diodes and said row of
optical detectors comprises four laser detectors.
11. A motherboard connector assembly for removably receiving and
electrically connecting an optical transceiver module, comprising a
first connector mounted to a motherboard; and a second connector
mounted to said motherboard, said second connector horizontally
displaced with respect to said first connector so that an optical
transceiver module having a housing open at an end, a first
electronic board fixed within said housing and having an edge
extending toward said open of said housing, and a second electronic
board fixed within said housing and having an edge extending toward
said open end of said housing beyond said edge of said first
electronic board, engages said first and second connectors with
said first and second electronic board respectively; whereby an
electrical connection is formed between said motherboard connector
assembly and said optical transceiver module.
12. The motherboard connector assembly of claim 11 wherein said
first connector carries signals for only one communication channel
to and from said first electronic board of said optical transceiver
module.
13. The motherboard connector assembly of claim 12 wherein said
first connector is disposed so to be able to engage an optical
transceiver module to form an SFP connection therewith.
14. The motherboard connector assembly of claim 13 wherein said
second connector carries signals for three communication
channels.
15. The motherboard connector assembly of claim 11 wherein said
first connector is disposed so to be able to engage an optical
transceiver module to form an SFP connection therewith.
16. The motherboard connector assembly of claim 15 wherein said
second connector carries signals for three communication
channels.
17. The motherboard connector assembly of claim 11 wherein said
first connector has a first slot for engaging said first electronic
board of said optical transceiver module and said second connector
has a second slot for engaging said second electronic board of said
optical transceiver module.
18. The motherboard connector assembly of claim 11 wherein said
motherboard is operative for a line card of a network device, said
network device selected from the group comprising a switch, router,
and crossconnect.
19. An optical transceiver module for removable mounting to a
motherboard, said optical transceiver module comprising: a housing;
first means fixed within said housing for making an electrical
connection to said motherboard, said first means forming an SFP
connection to said motherboard; and second means fixed within said
housing for making an electrical connection with said
motherboard.
20. A motherboard connector assembly for removably receiving and
electrically connecting an optical transceiver module, comprising a
first connector means mounted to a motherboard; and a second
connector means mounted to said motherboard, said second connector
means displaced with respect to said first connector so that an
optical transceiver module having a housing open at an end, a first
electronic board fixed within said housing and having edge
extending toward said open of said housing, and a second electronic
board fixed within said housing and having an edge extending toward
said open end of said housing beyond said edge of said first
electronic board, engages said first and second connector means
with said first and second electronic boards respectively to form
an electrical connection between said motherboard connector
assembly and said optical transceiver module, and so that an
optical transceiver module having a housing open at an end and only
one electronic board fixed within said housing and having an edge
extending toward said open end of said housing engages said first
connector means to form an SFP connection between said motherboard
connector assembly and said optical transceiver module.
Description
[0001] The present invention is a continuation-in-part of U.S.
patent application Ser. No. 10/847,948, entitled "MULTIPLE CHANNEL
OPTICAL TRANSCEIVER MODULES", filed on May 17, 2004, and assigned
to the present assignee.
BACKGROUND OF THE INVENTION
[0002] The present invention is related to optical transceiver
modules and their connections. More specifically, the invention is
related to optical transceiver modules with multiple channels
including a dual row pattern of optical emitters/detectors and
separate transmit and detect electronics and connections which are
adapted to such multiple channel, optical transceiver modules, as
well as currently single channel, optical transceiver modules.
[0003] As fiber optics developed, many new technologies emerged to
enhance their use. For example, fairly recently, a specification
for a new generation of optical modular transceivers was developed
named "small form-factor pluggable" (SFP). SFP transceivers are
designed to be high bandwidth, small physical size and easily
changeable (including being hot-swappable) on the line card of a
network device.
[0004] Unfortunately, integrated circuit (e.g., application
specific integrated circuit or ASIC) densities have increased to
the point that line cards are now optical port density limited,
rather than switch or processor limited. Thus, the electronics on
the motherboards of the line card have the capacity to process more
optical information than is currently being transmitted and
received from the optical ports of the line card. This extra
capacity is potential bandwidth that is not being realized. As a
result, many line cards that use conventional SFP optics have
unused bandwidth.
[0005] There have been many attempts to achieve higher optical port
densities. For example, parallel ferrule connectors have been
utilized to solve the problem of optical port density on the line
card faceplate. However, this typically requires fanout cables that
are bulky, expensive and may be unreliable.
[0006] Single-mode parallel solutions are available, but they have
typically been very large, expensive and difficult to manufacture.
Additionally, they may require permanently attached fiber pigtails
due to alignment requirements.
[0007] As a solution to solve the high cost of these early parallel
offerings, the parallel vertical cavity self emitting laser (VCSEL)
technology was developed. However, VCSEL technology blossomed at
shorter wavelengths (e.g., 850 nm) and enabled only very short
multi-mode applications. Also, the majority of VCSEL based parallel
optics are designed for parallel data transfer, where all channels
of data are synchronous or plesiochronous. These products,
therefore, typically do not allow multiple channels that are
totally independent (e.g., four independent, serial data channels).
Lastly, the reliability of this solution is still questionable.
[0008] It would be beneficial to have innovative techniques for
providing optical transceiver modules that provides multiple
channel optics without the disadvantages normally associated with
this capability. Additionally, it would be beneficial if the
optical and electrical crosstalk is reduced or eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1A shows an example of a parallel optical transceiver
module that is pluggable into a line card; FIG. 1B illustrate in
detail of one end of a parallel optical transceiver module; FIG. 1C
shows the details of a motherboard connector which receives the end
of the optical transceiver module of FIG. 1B.
[0010] FIGS. 2A and 2B show conventional ferrule patterns that
include transmitting and receiving optical fibers; FIG. 2C shows a
ferrule pattern of one embodiment of the invention for interfacing
with a row of four optical emitters and a row of four optical
detectors; FIG. 2D shows how the optical fibers from the ferrule
pattern in FIG. 2C can be dressed out as one or more fiber
pairs.
[0011] FIG. 3 illustrates an embodiment of the invention including
transmit and receive bars and separate electronic boards for
transmitting and receiving.
[0012] FIG. 4 shows the dual row orientation taking advantage of an
angled surface on the ferrule to reduce optical crosstalk in the
transceiver.
[0013] FIGS. 5A and 5B show an example of a cable that can be
connected to a parallel optical transceiver of the invention.
[0014] FIG. 6 illustrates another example of a cable that can be
utilized with embodiments of the invention.
[0015] FIG. 7 is a cross-sectional sideview of one end of an
optical transceiver module and corresponding motherboard
connectors, according to another embodiment of the present
invention.
DETAILED DESCRIPTION
[0016] In the description that follows, the present invention is
described with reference to embodiments that are used in
association with multiple channel optical transceivers for use with
line cards of network devices. However, embodiments of the
invention are not limited to any particular version, protocol,
environment, application, or implementation. For example, although
the invention is described in reference to specific embodiments,
the invention can be advantageously applied to many embodiments.
Therefore, the description of the embodiments that follows is for
purposes of illustration and not limitation.
[0017] Furthermore, it should be noted the same reference numerals
in different drawings for elements which are identical or similar
for ease of explanation.
[0018] FIG. 1A shows an example of a multiple channel optical
transceiver according to one embodiment of the present invention
that is pluggable into a line card 1 of a network device, such as a
switch, router, crossconnect, and the like. The line card 1
includes a motherboard 3 which has electrical
components/connections (not shown) and a bezel 5. A connector 7 is
mounted on motherboard 3 in order to electrically couple an optical
transceiver module 9 to the electrical components on the
motherboard 3. One end 12 of the optical transceiver module 9
(shown in greater detail in FIG. 1B) is pluggable into the
connector 7. A cage assembly 11 is mounted on the motherboard 3 to
protect and retain the optical transceiver module 9 when it is
inserted into the connector 7. As shown in FIG. 1C, the connector 7
on the motherboard 1 has two slots 10 for accepting parallel
electronic boards 27 that are housed within the optical transceiver
module 9. See FIG. 1B. Rows of pins 8 are associated with the slots
10 to make electrical contact with corresponding pins 6 on the
electronic boards 27 of the optical transceiver module 9. The
connector 7 can be a single two-row connector or two single-row
connectors one above the other.
[0019] FIG. 1B shows the end 12 of the optical transceiver module 9
in greater detail. The module 9 has a housing which is enclosed on
three sides, a "bottom" 21, and two sides 23. The end of a "top" 25
is open. Note that in FIG. 1A, the bottom 21 of the housing is
shown as being on top. Two parallel electronic boards 27 are
mounted in the housing one above the other and extend laterally
coextensively toward the edges of the housing bottom 21 and sides
23. The conducting pins 6 located at the edges of the electronic
boards 27 and are connected to leads on the boards 27. An internal
configuration of the optical transceiver module 9 is discussed in
more detail with reference to FIG. 3.
[0020] The opposite end 14 of the optical transceiver module 9 can
receive a plug 13. For example, the plug can be an MTP or MPO plug.
The plug 13 includes a ferrule 15 that retains and aligns the
multiple optical fibers in a cable. As shown, the optical
transceiver module 9 can include a latch 17 to assist in retaining
the plug 13 in the transceiver module 9 when inserted therein.
Other types of plugs and retention mechanisms can be utilized with
other embodiments.
[0021] The ferrule 15 retains optical fibers so they can interface
with corresponding optical emitters and optical detectors in the
optical transceiver module 9 in a particular manner described
below, according to an embodiment of the present invention. On the
other hand, FIGS. 2A and 2B show conventional ferrule patterns that
include transmitting and receiving optical fibers. In FIG. 2A, a
ferrule 101 retains eight optical fibers. Typically, the spacing of
the optical fibers in this arrangement is every 125 microns. Four
of the optical fibers 103 transmit to the optical transceiver
module and four of the optical fibers 105 receive optical
transmissions from the optical transceiver. In this configuration,
optical fibers that are similar are grouped together. FIG. 2B shows
a different ferrule pattern. A ferrule 111 includes four optical
fibers 113 that transmit to the optical transceiver module
alternating with four optical fibers 115 that receive optical
transmissions from the optical transceiver. In this configuration,
transmitting and receiving optical fibers are alternated.
[0022] The optical emitters and detectors within the optical
transceiver module are aligned with the optical fibers in the
ferrule. For example, a bar that includes both laser diodes and
detectors may need to be manufactured for the ferrule patterns of
FIGS. 2A and 2B. A problem results in that laser diodes and
detectors are generally incompatible, which makes hybrid bars
difficult to manufacture with resulting low yields. Additionally,
the spacing between transmitting and receiving optical fibers can
be fairly close (e.g., 125 microns), which can increase optical
crosstalk.
[0023] FIG. 2C shows a ferrule pattern of one embodiment of the
invention for interfacing with a row of four optical emitters and a
row of four optical detectors. A dual row ferrule 121 retains eight
optical fibers. A row of four optical fibers 123 that transmit to
the optical transceiver module 9 are disposed parallel to a row of
four optical fibers 125 that receive optical transmissions from the
optical transceiver module 9. As indicated by a dashed line 127, a
bar of laser diodes can be manufactured and then combined with a
bar of laser detectors which is manufactured separately from the
laser diode bar. Thus, manufacturing a hybrid bar is not
required.
[0024] Furthermore, the additional spacing between the laser diodes
and detectors results in reduced optical crosstalk. For example,
because the fabrication of every other laser diode or detector 129
can be skipped, the spacing can be 250 microns between adjacent
laser diodes and detectors (i.e., both within a row and
row-to-row). Additionally, this configuration creates multiple
transmit/receive pairs, which makes transitions to duplex fiber
cable much easier.
[0025] Conventional equipment and settings can be utilized to
manufacture these bars. As an example, the equipment for
manufacturing bars for the ferrules of FIGS. 2A and 2B can be
utilized to make the separate bars. When done in this manner, the
fabrication of every other laser diodes and detectors 129 as
described can be skipped to save costs. Alternatively, laser diodes
and detectors 129 can be manufactured on the bars, but not
utilized.
[0026] FIG. 2D shows how the optical fibers from the ferrule
pattern in FIG. 2C can be dressed out as one or more fiber pairs
which each form a bidirectional communication channel. As shown, a
pair 141 includes a transmitting optical fiber and a receiving
optical fiber. In some embodiments, four pairs are supported. Each
pair can be a line cord pair (e.g., similar to speaker wire) where
a user can separate the individual lines as the desired. By
allowing the transmit and receive optical fibers to go to different
locations, daisy-chained connections can be easily supported.
Parallel ribbon fiber optic cables require all ports to go to a
same port and requires receiving and transmitting optical fibers to
go to the same transceiver, which prevents daisy-chaining.
Conventional techniques, such as the use of two breakout cables,
couplers and cables, also do not provide the flexibility provided
by embodiments of the invention.
[0027] In other embodiments, the optical fibers are dressed out in
single lines (e.g., eight single lines). In still other
embodiments, mixed pairs and single lines can be present. Thus, the
optical fibers can be dressed out in different configurations
depending on the application (see also FIG. 6).
[0028] Now the description turns to further specifics of the
optical transceiver module 9 according to the present invention.
FIG. 3 illustrates one arrangement of the optical transceiver
module 9 which includes transmit and receive bars and separate
electronic boards for transmitting and receiving. As described with
respect to FIG. 1, the motherboard 3 has the connector 7 mounted
thereon. At the end 12 of the optical transceiver module 9, the
boards have edge connectors, pins 6, that provide the electrical
connection to the motherboard 3 via connector 7 when inserted into
the twin slots 10 of the connector 7. As shown in FIG. 1C, the
connector 7 has two slots 10 and associated rows of pins 8 for
accepting the parallel electronic boards 27 that are housed within
the optical transceiver module 9 (the dashed lines represent the
outline of the module 9 so that internal components can be seen).
One of the electronic boards 27 within the optical transceiver
module 9 is a transmitting electronic board 27T and the other is a
receiving electronic board 27R. Each board 27T and 27R has the
electrical circuitry and components to perform its associated
tasks. Flexible electrical connections 212 couple the transmitting
electronic board 27T to a transmitting bar 211, which can have a
row of laser diodes or LEDs (see, e.g., FIG. 2C). Similarly,
flexible electrical connections 214 couple the receiving electronic
board 27R to a receiving bar 213, which can have a row of laser
detectors.
[0029] The ferrule 15 (e.g., a MTP ferrule) is a part of the cable
plug 13 and retains the receiving optical fibers 123 and
transmitting optical fibers 125 so they can optically couple to the
receiving bar 213 and transmitting bar 211 respectively. Electrical
crosstalk within the optical transceiver module 9 is reduced or
eliminated because the transmitting and receiving electronics are
on separate, parallel boards as shown. Conventional optical
transceivers modules include an electronic board with both
transmitting and receiving circuitry/components, which facilitates
electrical crosstalk.
[0030] FIG. 4 shows how the dual row orientation in some
embodiments of the present invention can take advantage of an
angled surface on the ferrule 15 to reduce optical crosstalk in the
optical transceiver module 9. Receiving optical fibers 123 delivers
light to the receiving bar 213. Similarly, light from the
transmitting bar 215 is delivered to transmitting optical fibers
125. In the cross-sectional view of FIG. 4, only a pair of
receiving and transmitting optical fibers 123 and 125 are shown.
The receiving bar 213 and transmitting bar 215 are on a substrate
259 and communicates to the electronic boards 27R and 27T through
the flexible electrical connections 212 and 214 shown in FIG.
3.
[0031] The ferrule 15 retains the optical fibers and is angled at
the end proximal to receiving and transmitting bars 213 and 215,
respectively. The orientation of the receiving and transmitting
bars to the angle of the ferrule is designed so that light
reflected at the aperture of transmitting optical fiber 125 is
directed away from the aperture of receiving optical fiber 123.
Thus, optical crosstalk can be reduced by the specific orientation
of the optical emitters and detectors relative to the angled end on
ferrule 15.
[0032] FIGS. 5A and 5B show an example of a cable that can be
connected to the parallel optical transceiver module 9 of the
invention.
[0033] With regard to FIG. 5A, the optical transceiver module 9
includes an adapter 303 at the end 14 for receiving the end of a
cable housing 305. The cable housing 305 includes a dense face
mountable interconnect 307 for connecting to the adaptor 303. The
ferrule 15 retains the optical fibers for optical coupling to
optical emitters and detectors in optical transceiver module 9. As
shown, the cable housing 305 has a 90.degree. bend, which may be
desirable for routing the cables. Eight cables 123 and 125 are
shown extending out of a furcation block 313. These cables can be
dressed out as four independent duplex cables for connection to
line cards in other network devices. In other embodiments, there
can be fewer or more cables, the cables can be dressed out as pairs
or as single cables, or any combination depending on the
application.
[0034] FIG. 5B shows the dense face mountable interconnect 307 of
cable housing 305 inserted into the optical transceiver module 9.
These figures illustrate one way of connecting the optical
transceiver module to the optical fibers in the cables, but other
techniques may be advantageously utilized with the invention.
[0035] For example, in one embodiment, a MTO or MTP plug 13 is
utilized that fans out into four duplex cables. FIG. 6 illustrates
an example of this cable. The plug 13 houses the ferrule 15 that
retains the optical fibers 123 and 125. The parallel cable of the
optical fibers is separated out into individual optical fibers by a
furcation block 404. The furcation block 404 can provide buffering
and strain-relief in addition to routing the optical fibers into
standard "yellow jacket" cabling. Pairs of eight transmitting and
receiving optical fibers 123 and 125 are dressed out into four
duplex cables 405 as shown. As mentioned previously, the optical
fibers may be also dressed out as eight single cables or many other
configurations.
[0036] Still another embodiment of the present invention is found
in the connections between the optical transceiver module 9 and the
motherboard 3 of the line card 1. FIG. 7 illustrates a
cross-sectional side view of the end 12 of the optical transceiver
module 9 and connectors on the motherboard 3. In this embodiment,
the two electronic boards 27, labeled 27A and 27B in this drawing,
are staggered laterally. The "upper" board 27B closest to the
module housing "bottom" 21 extends close to the edge of the housing
bottom 21 and sides 23, while the "lower" 27A does not extend as
far toward the housing edge. Two connectors 7A and 7B are mounted
on the motherboard 3 to make the connections to the electronic
board 27A and 27B respectively. The first connector 7A has a slot
10A at a height h1 so as to receive the first electronic board 27A.
The second connector 7B which is laterally displaced from the first
connector 7A by a displacement D has a slot 10B at a height h2 to
receive the second electronic board 27B. The edge of the second
electronic board 27B is closer to the edge of the module housing,
of which the "bottom" 21 is shown. When the optical transceiver
module 9 is fully inserted into the cage 11 (not shown in FIG. 7,
see FIG. 1) and electrical connection is made, the upper electronic
board 27B passes over the connector 7A and is seated in the slot
10B of the connector 7B, while the lower electronic board 27A is
seated in the slot 10A of the second connector 7A.
[0037] The electrical and optical connections of the optical
transceiver module 9 can remain as described previously; the only
differences being the locations of the electronic boards 27A and
27B and connectors 7A and 7B correspondingly. However, an advantage
of the arrangement shown in FIG. 7 is that it can be fully
compliant with existing standard SFP connections. That is, the
electronic board 27A is set at the height h1 so that the electronic
board of an optical transceiver module with a standard SFP
connection engages the motherboard connector 7A. The vertical solid
line marked 30 in FIG. 7 illustrates the edge of an optical
transceiver module housing with such a standard SFP connection. In
such a connection, the upper electronic board 27B is nonexistent so
that the motherboard connector 7B is not engaged. Hence the
connector 7A can receive a single electronic board of an SFP
connection, or the connector 7A can receive one of two electronic
boards staggered in an optical transceiver module, for a multiple
channel connection, while the connector 7B receives the upper
electronic board.
[0038] However, besides the physical compatibility with standard
SFP connections, the electrical connections to connectors 7A and 7B
must be modified. Since the standard SFP connection handles one
bidrectional communication channel, i.e., one receiving signal and
one transmitting signal, the electronic board 27A and the
corresponding connector 7A which engages the board 27A must carry
one receiving and one transmitting signal. For the functional
capacity of the previously described multichannel optical
transceiver module, the "upper" electronic board 27B and
corresponding connector 7B must handle the other three channels,
i.e., three receiving and three transmitting signals. Thus the
upper electronic board 27B has three extra pins for the additional
signal paths, as compared to the electronic boards described
earlier. The electrical connections between the electronic boards
and the transmitting and receiving bars 211 and 213 must also be
correspondingly modified. Cf. FIG. 3. Since each board 27A and 27B
must carry receiving and transmitting signals, the separation of
functions for one electronic board for transmitting and the other
for receiving cannot be maintained. Nonetheless, the described
arrangement permits a standard SFP connection to the motherboard 3
and a multiple connection to the motherboard 3.
[0039] Therefore, while the description above provides a full and
complete disclosure of the preferred embodiments of the present
invention, various modifications, alternate constructions, and
equivalents will be obvious to those with skill in the art. Thus,
the scope of the present invention is limited solely by the metes
and bounds of the appended claims.
* * * * *