user manual

5-2 \ Zhone Technologies
Model No.
Running Head
T1 loopbacks Diagnostics
Figure 5-1. T1 loopbacks
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)
T1 Loopback
T1 Network
Transmit
Receive
Transmit
Receive
LIU
FRAMER
CPU
CPE Device
T1 Network
Transmit
Receive
Transmit
Receive
LIU
FRAMER
CPU
CPE Device
Network or Remote 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.
Local Loopback
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.