Appendix
Null Modem Cable
Figure B-1
ports on the PXM-UI-S3 and PXM-UI-S3/B User Interface Cards.
Figure B-1
1
7
2
3
6
20
Pin Assignments for RJ-48 Maintenance and Control Ports
Table B-4
Table B-4
Pin No.
1
2
3
4
5
6
7
8
External Clock Input Cabling
This section explains the cabling that provides the MGX switch with an external clock source.
If external equipment or a local digital central office provides synchronization to the Cisco MGX switch,
the external clock source is connected to the user interface back card (PXM-UI-S3 or PXM-UI-S3/B).
The user interface back card has two external clock input ports labeled EXT CLK1 and EXT CLK2 that
can support either T1 or E1 external clock input, but not both. That is, both EXT CLK1 and EXT CLK2
clocks must be set the same, either T1 or E1. The clock may be 1.544 Mbps or 2.048 Mbps. Refer to
Table 2-44 on page 2-120
back card, and see
clock ports.
The PXM-UI-S3 or PXM-UI-S3/B cards go into slots 7 and 8 for the following switches:
•
•
Releases 2 - 5.2, Part Number OL-4545-01, Rev. H0, May 2006
shows a null modem cable that is used for connecting modems to the control or maintenance
Null Modem Cable
provides the pin assignments for the associated RJ-48 and RJ-45 connectors.
Pin Assignments for the RJ-48 Maintenance and Control Ports on the PXM-UI-S3 and
PXM-UI-S3/B User Interface Cards
Name
Description
RTS out
Request to send
DTR out
Data terminal ready
TxD
Transmit data
GND
Chassis ground
GND
Chassis ground
RxD
Receive data
DSR
Data set ready
CTS
Clear to send
for information about which switch is compatible with which user interface
Figure 2-63 on page 2-121
MGX 8850 (PXM1E/PXM45) and MGX 8850/B
MGX 8950
1
7
2
3
6
20
and
Figure 2-64 on page 2-122
Cisco MGX 8800/8900 Series Hardware Installation Guide
Control and Clock Cabling
for locations of the external
B-5