Multi-Tech Systems MT56DSU-S manual Line Loopback Test, DSU Loopback Test

Chapter 4 - Diagnostics

4.1.2 Line Loopback Test

This test enables you to test the local DTE, the local DSU, the communications link, and the remote DSU. Use the following steps to perform the Trunk Loopback Test.

1.Set DIP switch #3 on the remote DSU to the down position.

2.Send data from the local DTE, it should be looped back to the local DTE. If you have access to a Bit Error Rate Tester, this can be used in place of the local DTE.

		Network
Local DTE	Local DSU		Remote DSU
(or BERT Tester)		(In Line Loopback Test Mode)

Figure 4-2. Line Loopback Test Diagram

4.1.3 DSU Loopback Test

This test lets you verify proper DSU operation by matching a transmitted signal to the “looped-back” receive signal. Refer to Appendix B for cable description.

1.Obtain a DSU Loopback cable (#45640100) from Multi-Tech, or assemble one. Refer to Appendix B for instructions on building the Loopback cable.

2.Plug the Loopback cable into the back panel Line jack.

3.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.

Loopback

Cable

DTE	DSU
	being tested

Figure 4-3. DSU Loopback Test

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