Multi-Tech Systems DT101/xx, DT102/xx owner manual Test Cables, Troubleshooting

Chapter 7 - Troubleshooting

7.3 Test Cables

If you are using the DataTalker internal DSU or MMH2834 modem, there are three test cables you can use to check out your system. Two DataTalker back-to-back test cables allow you to connect your two DataTalkers locally before installing them on either end of a phone line. There is also a composite link loopback cable that you can use with the internal DSU to loop the DataTalker composite link signal back to itself.

To test the internal DSU back-to-back, connect the DSUs in the two units with the RJ-45 back-to- back cable, then configure one DSU for internal clocking and the other DSU for external clocking. Set the speed to the same value on both units. To perform the composite link loopback test, configure the DSU for internal clocking and use the composite link loopback cable.

To test the internal MMH2834 modem back-to-back, use the RJ-11 back-to-back cable and configure both modems for 4-wire leased line operation. Configure one modem for originate and the other modem for answer. Set the speed to the same value on both units and set transmit level to -10. To test 2-wire leased line operation, substitute a regular RJ-11 cable in place of the back-to-back cable and reconfigure the modem for 2-wire operation.

If you are using an external synchronous modem for the link communications, refer to its documentation for testing procedures.

If you have any problems in performing these procedures, contact Multi-Tech’s Technical Support department for assistance (see Chapter 8).

Test Cable for Internal DSU or MMH2834 Modem

Test Cable

DataTalker DataTalker

Internal Composite

Connector

Note: Used locally before installation to verify operation of entire system except composite link.

Composite Link Loopback Cable with Internal DSU

Internal Composite

Connector

DataTalker	Composite Link	DataTalker
	Loopback Cable

Figure 7-1. Off-Line Test Modes

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