This document describes how to identify and troubleshoot various alarms
on a T3 line.
There are no specific requirements for this document.
This document is not restricted to specific software and hardware
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
For more information on document conventions, refer to the
Technical Tips Conventions.
Based on the type of Port Adapter used, the following Cisco IOS®
software commands display the T3 interface status specific to the controller
This information is useful for diagnostic tasks performed by the
technical support personnel.
This section addresses the various types of alarms, and outlines the
procedures to correct them.
A receive (rx) Loss Of Signal (LOS) alarm indicates that the RX port on
the Port Adapter does not receive a valid physical T3 signal.
To clear the rxLOS alarm, complete these steps:
Ensure that the cable between the interface port, and the T3
Service Provider's equipment (or remote T3 terminal equipment) is connected
correctly. Ensure that the cable is hooked up to the correct ports. Correct the
cable connections if necessary.
Check the 75 ohms coaxial cable integrity. To do so, look for
breaks or other physical abnormalities in the cable. Replace the cable if
A receive (rx) Loss Of Framing (LOF) alarm implies that the input port
is not receiving framing, or has lost synchronization on the received
To clear the rxLOF alarm, complete these steps:
Check whether the framing format configured on the port matches the
framing format on the line.
Try the other framing format, and check whether the alarm
Work with your service provider to configure a remote loopback on
the affected interface. Then run an unframed bit error rate tester (BERT). This
test will enable you to determine whether there are problems on the
If this does not fix the problem, see the rxLOS/Receiver has Loss of Signal
A receive (rx) Alarm Indication Signal (AIS) alarm indicates an error
occurring on the T3 line upstream from the equipment that is connected to the
The AIS alarm is declared when an AIS signal (all 1s) is detected at
the input, and still exists after the Loss Of Frame alarm is declared active
(caused by the unframed nature of the all 1s signal). The AIS alarm is cleared
when the Loss Of Frame alarm is cleared.
To clear the rxAIS alarm, ask your service provider to check for an
incorrect internal configuration (within the telephone company), or a failure
in their upstream connections.
Also, ask your service provider to trace the source of the AIS
A receive (rx) Remote Alarm Indication (RAI) alarm means that the
far-end equipment has a problem with the signal that it receives from the local
RAI indicates a problem between the the transmitter of the router
interface, and the far-end T3 receiver. However, the problem may not be in the
segment between the router and the adjacent node.
To clear the rxRAI alarm, complete these steps:
Insert an external loopback cable into the port. For more
information, see the
Plug Loopback Tests for T3 Lines section of the
Error Events Troubleshooting document.
Check whether there are any alarms. If you do not see any alarms,
the local hardware is probably in good condition. In that case, complete these
Check the cabling. Ensure that the coaxial cable between the
interface port and the T3 service provider's equipment (or T3 terminal
equipment), is connected correctly. Ensure that the cable is connected to the
correct ports. Correct the cable connections if necessary.
Check the cable integrity. To do so, look for breaks or other
physical abnormalities in the coaxial cable. Replace the cable if
Check the settings at the remote end, and verify whether they
match your port settings. If the problem persists, contact your service
Remove the loopback cable, and reconnect your T3
Check the coaxial cabling.
Power cycle the router.
Connect the T3 line to a different port. Configure the port with
the same settings as the T3 line. If the problem is resolved, the fault lies
with the port. In this case, complete these steps:
Reconnect the T3 line to the original port.
Perform a hardware loop test. For more information, see
Plug Loopback Test for T1 Lines
A transmit (tx) remote alarm indication (RAI) at a T3 interface
indicates that the interface has a problem with the signal that it receives
from the remote equipment.
To clear the txRAI alarm, complete these steps:
Check the settings at the remote end to ensure that they match your
A txRAI alarm is caused by an active receiver alarm. This alarm
indicates the problem that the T3 port/card has with the signal from the
far-end equipment. Troubleshoot the condition to resolve the
A transmit (TX) Alarm Indication Signal (AIS) is declared when the T3
serial interface is shut down (PA-T3 only), and consists of sending all ones
(1s) in an unframed T3 signal.
To clear the txAIS alarm, use the no
shutdown command to bring the T3 serial interface up.
Note: When the T3 controller on PA-MC-T3 is shut down, it does not send a
T3 electrical signal on its TX port.