Information Technology Reference
In-Depth Information
If Receiver Has Loss of Frame
Check to see whether the framing format configured on the port matches the framing format of the line.
You can check the framing format of the controller from the running configuration or the
show
controller t1
command output.
To change the framing format, use the
framing {SF | ESF
} command in the controller configuration
mode, as shown here:
Step 1
maui-nas-03#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
maui-nas-03(config)#
controller t1 0
maui-nas-03(config-controlle)#
framing esf
Try the other framing format to see if the alarm clears.
Step 2
Change the line build out setting using the
cablelength {long | short}
command.
Line build out (LBO) compensates for the loss in decibels based on the distance from the device to the
first repeater in the circuit. A longer distance from the device to the repeater requires that the signal
strength on the circuit be boosted to compensate for loss over that distance.
To configure transmit and receive levels for a cable length (line build out) longer than 655 feet for a T1
trunk with a channel service unit (CSU) interface, use the
cablelength long
controller configuration
command. To configure transmit attenuation for a cable length (line build out) of 655 feet or shorter for
a T1 trunk with a DSX-1 interface, use the
cablelength short
controller configuration command.
Consult your service provider and the Cisco IOS command reference for details on buildout settings.
If this does not fix the problem, proceed to the next section.
Step 3
If Receiver Has Loss of Signal
Step 1
Make sure that the cable between the interface port and the T1 service provider's equipment or T1
terminal equipment is connected correctly. Check to see if the cable is hooked up to the correct ports.
Correct the cable connections, if necessary.
Step 2
Check cable integrity. Look for breaks or other physical abnormalities in the cable. Ensure that the
pinouts are set correctly. If necessary, replace the cable.
Step 3
Check the cable connectors. A reversal of the transmit and receive pairs or an open receive pair can cause
errors. Set the receive pair to lines 1 and 2; the transmit pair should be lines 4 and 5.
The pins on an RJ-48 jack are numbered from 1 through 8. Pin 1 is the leftmost pin when looking at the
jack with the metal pins facing you. Refer to Figure 15-11.
Figure15-11RJ-45 Cable
87654321
RJ-45 connector
Step 4
Try using a rollover cable.
