Loop (V.54 & Telco) Diagnostics
The 2073RC offers two loop diagnostics for diagnosing the 2073RC and any communication links. These tests can be activated via signals on the serial port interface or the front panel switch.
Operating Local Loopback (LLB)
The Local Loopback (LLB) test checks the operation of the local 2073RC and is performed separately on each unit. Any data sent to the local 2073RC in this test mode will be echoed (returned) back to the user device (i.e.,characters typed on the keyboard of a terminal will appear on the terminal screen).
Figure 12. Local loopback
To perform a LL test, follow these steps:
1.The Local Loop can be initiated from the 2073RC unit either by acti- vating the LL signal on the DTE (if you are not sure which lead is the RDL signal, please refer to the Appendix,) or by toggling the top front panel switch towards the label “LLB”. The Yellow TM (Test mode) LED will turn on to indicate a successful Local loop condition.
2.Verify that the data terminal equipment is operating properly and can be used for a test.
3.Perform a V.52 BER (bit error rate) test bit error rate (V.52) diagnos- tics.If the BER test equipment indicates no faults, but the data termi- nal indicates a fault, follow the manufacturer’s checkout procedures for the data terminal. Also, check the interface cable between the terminal and the 2073RC.
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