Cisco CISCO2650 - 2650 Router Hardware Installation Manual page 134

Channelized E1/ISDN PRI Balanced (120-Ohm) Network Modules
CE1/PRI Module Jumper Settings
Jumpers on CE1/PRI modules can be used to connect or disconnect receive shield to ground. (See
Table
ground. The default setting for unbalanced, 75-ohm CE1/PRI-U modules connects receive shield to
ground. If you are experiencing ground loop problems with E1 cabling, you may want to try changing
the jumper settings for the module.
Table 7-2
CE1/PRI Module Type Default Setting Function
Balanced, 120-ohm
Unbalanced, 75-ohm 1 and 2
Connecting CE1/PRI-B Modules to the Network
To connect a CE1/PRI-B (120-ohm) module to the network, use the appropriate cable to connect the
CE1/PRI-B port to an E1 CSU. (See
and RJ-45 CSUs, respectively.) These ports are color-coded tan.
Figure 7-13 Connecting a 120-ohm CE1/PRI-B Module to an E1 CSU (DB-15-to-DB-15 Connectors)
FE-PR I
1FE-1 CE1-B /U
Cisco Network Modules Hardware Installation Guide
7-10
7-2.) The default setting for balanced, 120-ohm CE1/PRI-B modules disconnects receive shield to
CE1/PRI Module Jumpers
2 and 3
CTRLR 0
CE1/PRI-B (DB-15)
E1 cable for 120-ohm
balanced connections
with a DB-15 connector
at the network end
DB-15 connector
Chapter 7
Disconnects receive shield from ground
Connects receive shield to ground
Figure 7-13, Figure 7-14, and
10/100B aseT
EN
E1 CSU
Connecting ISDN PRI Network Modules
Figure 7-15, showing DB-15, twinax,
OL-2485-20