ADC Campus-REX2 RS, User Manual

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Chapter 5 - Monitoring and Testing the Campus System
Campus-REX2 RS Interface Card User Manual 87
Performing Loopback Testing
Loopbacks provide testing for the HDSL data communication path between
the Campus unit, the remote unit, and the remote host equipment. Loopback
tests can be run only when one end of the HDSL connection (either the local
or the remote) is a Campus-REX2 or Campus-REX (both ends cannot be
Campus-REX2 or Campus-REX).
The following section describes how to set up, run, and terminate
loopback tests.
Configuring Loopbacks
The Campus-REX2 supports the following types of loopbacks between a
Campus-REX2 and another Campus unit that contains a synchronous
interface card such as V.35 or DSX-1:
• The Remote to Remote loopback tests the remote data port.
• The Local to Remote loopback tests the remote data port, the entire data
path inside the remote Campus unit, the HDSL line, the HDSL
transceivers of both units, and most of the internal data path inside the
local unit. This loopback does not test the local data port drivers and
receivers.
Once a loopback condition has been initiated, it remains in effect until it is
cleared. You may also set a loopback timeout to clear the loopback
automatically after a set period of time has elapsed.
If both the local and remote Campus units have a
Campus-REX2 RS Interface Card, no loopbacks are
supported between the two units.