Chapter 4 - Diagnostics
4.1Introduction
The DSU is set to a default of Normal
When a failure occurs in the digital facility (Telco equipment), the network will detect the failure and send a repetitive OOS signal sequence to your equipment. Your equipment can detect local loop failure by the absence or distortion of the digital signal. If an OOS is received when data is expected, check the remote (far- end) transmitting equipment. If the remote equipment is transmitting properly, contact your telephone company. If the Telco is required to perform remote tests, the channel will be temporarily interrupted and loss of data may occur.
The following sections describe the tests that are available for the DSU.
4.1.1 Loopback Test
This test allows you to test the local DTE and local DSU. Use the following steps to perform the Loopback Test.
1.Set DIP switch #3 to the down position.
2.Send data from your DTE, it should be “looped back” to your DTE. If you have access to a Bit Error Rate Tester, this can be used in place of the DTE.
DTE | Local DSU |
(Or BERT Tester) | (In Loopback Test Mode) |
Figure 4-1. Loopback Test Diagram
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