Enterasys Networks XSR-3020 - Manual (Page 103)

Cable, CompactFlash and Accessory Specifications
XSR Getting Started Guide A-17
Termination Shunt for the ISDN BRI-S/T NIM Card
ISDN BRI-S/T terminal equipment devices may be connected at random points of the cable in
point-to-point or point-to-multipoint configurations. Line termination resistors must be provided
at both ends of the transmit/receive lines only.
The XSR’s BRI NIM card provides an option to terminate receive as well as transmit lines using
100 Ohm resistors. Shunts are required to shorten the appropriate contacts of the terminal headers
(P1, P2). Refer to “
Installing Shunt/Terminal Strip ” on page A-17 for directions.
Figure A-20 below shows per port respective termination header locations and the orientation of
the receive and transmit pairs.
Installing Shunt/Terminal Strip
To install the shunt or terminal strip, attach two dual-pin units vertically to P1 and P2 four-pin
jumpers corresponding to the RJ-45 port using a balun, as shown in
Figure A-20 . Any other RJ-45
ports on the NIM card connected to 120-ohm lines do not require shunts.
Figure A-20 Installing a Termination Shunt on BRI-S/T NIM Card
Caution: The cable connecting the BRI NIM to the balun requires two additional wires to extend
the chassis ground to the balun. Cables of this type are often provided by your supplier who can
customize them for your needs.
P2 P1
T1
T2 F14 F16
CR
1
F17
J1 J2
Receive Pair Termination
Transmit Pair Termination
Port 0 Port 1
CR
2
R1
32
R1
33
F15
F1 F2 F3 F4 F5 F6 F7 F8
Port 1 Port 0