Cisco 2600 Series Operation Manual page 97

Table 8-5
LED
REMOTE ALARM
LOCAL ALARM
LOOPBACK
CARRIER DETECT
CE1/PRI Module Jumper Settings
Jumpers on the CE1/PRI modules can be used to connect or disconnect receive shield to
ground. (See Table 8-6.) The default setting for balanced, 120-ohm CE1/PRI-B modules
disconnects receive shield to 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 in the
module.
Table 8-6
CE1/PRI Module Type
Balanced, 120 ohm
Unbalanced, 75 ohm
ISDN PRI Network Module LEDs
Meaning
Local alarm at remote end of connection
Loss of signal, loss of frame, or unavailability
because of excessive errors
Controller local loopback
Carrier received on telco link
CE1/PRI Module Jumpers
Default Jumper Setting
2 and 3
1 and 2
Connecting ISDN PRI Network Modules to a Network 8-17
CE1/PRI Module LEDs
Function
Disconnects receive shield from
ground
Connects receive shield to ground