Black Box MD1641A, MD1640A manual Modem Testing

SERIES II INTELLIGENT DATA/FAX MODEMS

8.Modem Testing

8.1Introduction

Each time you power up the Series II Modem, it performs an automatic self- test to ensure proper operation. The Modem also has four diag- nostic test features: Local Analog Loopback, Digital Loopback (remote/automatic), Digital Loopback (local/manual) and a modem Back-to-Back test.

A loopback test involves entering data from your PC and looping that data through the circuits of your modem and/or a remote modem. When the loop has been completed, the original data entered should match the data received back on your PCs monitor after the test.

The Local Analog Loopback Test allows you to verify that the modem’s transmitter and receiver circuits are functioning properly.

The Digital Loopback Test (local/manual) allows you to verify that the remote computer or terminal, the remote modem, serial ports, the telephone line and the local modem are functioning properly.

The Digital Loopback Test (remote/automatic) allows you to verify that the local computer or terminal, the two modems and the transmission line between them are functioning properly.

The Back-to-Back test lets you connect two Series II Modems with a back-to-back cable to verify proper modem operation.

In asynchronous mode, upon completion of testing, enter either Escape Sequence, +++AT<CR> or <BREAK>AT<CR>.

Note: All loopback tests will operate at all speeds except 300 bps. Disable error correction (&E0&W0<CR>) before engaging in loopback tests (self-test and back-to-back test not affected).

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