Digital Link DL3800 DS1, User Manual

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Diagnostics 6-3
6
Payload Loopback and Line Loopback Tests
Use the PAYLOAD Loopback and LINE Loopback tests to verify the proper
operation of the DL3800 and selected T1 networks.
Both tests loop the payload data received from the T1 network back to the
network.
With the PAYLOAD Loopback, the DL3800 regenerates the data and inserts
a new framing pattern before it loops back the data. This veriÞes the unitÕs
T1 framing and the T1 network.
With the LINE Loopback, the DL3800 does not do any additional
processing of the data before it regenerates it and loops it back. This
minimizes the involvement of the DL3800 during this test so that problems
can be isolated to the network.
Possible Sources of Problems
The PAYLOAD Loopback can test a problem whose source may be the
DL3800.
The LINE Loopback can test a problem whose source may be the Telco T1
line, wiring between the Telco demarcation points, the DL3800 at one or
both ends, or the cable between the T1 line reporting errors and the
DL3800.
The TEST LED on the DL3800 turns red during the tests, and the T1 port
LED turns yellow.
T
ROUBLESHOOTING THE
DL3800
This section describes problems you may encounter on the DL3800 and
suggests ways you can troubleshoot them.
The troubleshooting procedure is designed to isolate the faulty or
malfunctioning item to the T1 network, the DTE equipment, the cable from
the DTE to the DL3800 or the DL3800 itself. The built-in diagnostic features
of the DL3800 aid the user in quickly identifying and isolating faults.
Using the front panel buttons and display, the ASCII terminal or SNMP
workstation, the user can run a series of loopback tests. VeriÞcation of the
proper functioning of the DTE equipment and the DL3800 is accomplished
through DTE loopback and a self test. Testing for the proper functioning
of the remote DL3800 is accomplished by a Line loopback.