T1 loopbacks | Diagnostics |
Figure 5-1. T1 loopbacks
T1 Loopback
T1 Network
Receive | Transmit |
| LIU |
| FRAMER |
| CPU |
Receive | Transmit |
CPE Device
T1 Network
Receive | Transmit |
| LIU |
| FRAMER |
| CPU |
Receive | Transmit |
CPE Device
Network or Remote Loopback | Local Loopback |
The incoming T1 Signal is looped inside the T1 Framer and returned to the T1 Network. This exercises the T1 Line Interface Unit and the T1 Framer with the exception of the HDLC controller and clock switching circuitry.
The outcoming T1 Signal is looped inside the T1 LIU and returned to the CPE Device. This exercises the T1 Line Interface Unit, T1 Framer, CPU, Data Port Interface, and the FXS Interface with the exception of the HDLC controller.
To activate a loopback, enter the following command:
user> SET T1CFG:LOOPBACK:x:(LINEON/LOCALON)
where x is the number of the T1 interface to loopback. To end the loopback, enter the following command:
user> SET T1CFG:LOOPBACK:x:(LINEOFF/LOCALOFF)
