RAD Data comm ASMi-31 operation manual Loopback LLB, To perform the Local Analog Loopback test

Chapter 4. Tests and Diagnostics		ASMi-31Installation and Operation Manual
Local Analog	The Local Analog Loopback (LLB) test checks the performance of the local
Loopback (LLB)	ASMi-31, the local DTE, and the connections between them (see
	Figure 4-1). Perform the test separately at the local and the remote site.

Data

Clock Transmit

DTE

Clock

Data Receive

ASMi-31

Line

Interface

Figure 4-1 Local Analog Loopback

➤To perform the Local Analog Loopback test:

• Activate the test via the DTE interface analog loopback.

The TEST LED lights up.

The ASMi-31 modem transmit output is connected to the receiver circuits internally at the line side. If a fault is indicated, call a technician or replace the unit.

Set the DTE equipment in half duplex (which produces an "echo" through the system). It is recommended that you repeat the LLB test using an external Bit Error Rate Tester (BERT).

Perform the test at both ends. If the BERT equipment test indicates no faults, but the data terminal indicates a fault, follow the DTE manufacturer's test procedures . Also check the interconnecting cable interfacing between the terminal and the ASMi-31 modem.

After completing the test (or when the fault has been corrected), deactivate the LLB via the DTE interface and proceed to the Remote Loopback (Communication Link) Test.

4-2 Diagnostic Tests

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