Using Loopback Commands - Cisco PA-4E1G Series Installation And Configuration Manual

Chapter 4 Configuring the PA-4E1G

Using loopback Commands

With the loopback test, you can detect and isolate equipment malfunctions by testing the connection
between the PA-4E1G interface and a remote device such as a modem or CSC/DSU. The loopback
subcommand places an interface in loopback mode, which enables test packets that are generated from
the ping command to loop through a remote device or compact serial cable. If the packets complete the
loop, the connection is good. If not, you can isolate a fault to the remote device or compact serial cable
in the path of the loopback test.
The E1-G.703/G.704 interface supports the same local loopback test as other (data communications)
interfaces. Using the loopback functions, you can check the integrity of the physical data path between
the motherboard (or chassis system) and the PA-4E1G with the loopback command. The loopback signal
follows this path regardless of whether or not a cable is attached to the port.
Figure 4-1
loopback tests on the interface.
Because each E1-G.703/G.704 interface uses a default clock rate of 2.048 Mbps, you do not have to
Note
configure a clock signal on the interface before performing a loopback test.
Figure 4-1
Motherboard
or chassis midplane
OL-3065-05
shows the signal path of the loopback function. The no loopback command disables all
Loopback Path
Loopback
EI-G.703/G.704
port adapter
PA-4E1G Serial Port Adapter Installation and Configuration
Checking the Configuration
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