Owner`s manual

MT64DSU Owner's Manual

Diagnostic Tests

The MultiDSU64K is set to a default of Normal (non-diagnostic)

mode at the factory.

When a failure occurs in the digital facility (DDS circuit), the network

detects the failure. Your equipment can detect failure by the

absence or distortion of the digital signal. If the remote equipment is

not 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 diagnostic tests available for the

MultiDSU64K.

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. Note: The DSU must be in 4-wire

dedicated line mode to perform this test.

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. If you 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.

Figure 3-1. DSU Loopback Test with Loopback Cable

Loopback

Cable

DSU

being tested

DTE