Black Box MD1000C Guida Utente Scaricare il pdf (Pagina 118)

Test Mode Operation

7-4 Modem 3600

For 2-wire operation, Analog Bilateral Loopback is invalid. In 4-wire

operation, Analog Bilateral Loopback connects the receive line to the

transmit line through a buffer amplifier.

Test the local DTE and cable by entering the &T1 command. Enter a test

message and verify it is echoed on the screen. If it is not returned

exactly as entered, the terminal equipment or data cable is at fault.

To determine if the data cable is defective replace it with a properly

configured cable with electrical continuity. If the cable checks out but

the problem remains, the DTE is defective.

If all local equipment checks out, proceed to the“Testing the Remote

Modem” section on page 7-5.

Issue an escape sequence followed by &T1 to exit analog loopback.

Local Analog Loopback with Self Test &T8

When the modem is offline in command mode, enter the &T8 command

to put the modem in Self Test Local Analog Loopback (Figur e 7-2).

The modem transmits a test pattern. The test pattern is looped back to

the receiver and checked for errors. Entering the &T command causes

the modem to exit Self Test Analog Loopback. The modem responds

with a three digit value between 0 and 255 representing the number of

errors during test pattern detection. If errors occur, repeat the test to

verify the consistency of the problem.

Figure 7-2. Local Analog with Test Pattern

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Black Box MD1000C Guida Utente Pagina 118