Loopback Test - Nortel Meridian Meridian 1 Maintenance Manual

146 Chapter 3: Link maintenance commands

loopback test

553-3211-510 Standard 1.0 October 1998
This test verifies the condition of synchronous links, typically link 0
(AML) and link 1 (host link) on the Application Module or IPE Module.
If the Meridian Link system is running with a host link over Ethernet
TCP/IP, the user has the option to run a loopback ping test which invokes
the UNIX ping command to verify that the host is operational.
This diagnostic test entails connecting a loopback cable between two
synchronous ports on the Application Module or IPE Module (typically
link 0 and link 1), and running a test from the mlusr> prompt to test the
ports.
The loopback cable is a 25-pin RS232C, male-to-male straight cable for
both the Application Module and the IPE Module.
The loopback test will configure both link 0 and link 1 as HDLC protocol
links, and try four different combinations of DTE and DCE settings until
the link establishes. If the link does not establish, the test is deemed to have
failed, and the reason for the failure will be provided. Refer to Chapter 6,
ÒLink error messagesÓ for descriptions of the error messages.
After the test is completed, the two links are restored to their original
configurations.
Note: One port must be configured as DTE and the other as DCE.