Black Box 3600 manual Local Analog Loopback with Self Test &T8, Local Analog with Test Pattern

Test Mode Operation

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 (Figure 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

7-4 Modem 3600