Multitech MT1432BA - Manual (Page 98)

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MultiModemBA User Guide
8.1 Introduction
Each time you power up the MultiModem, it performs an automatic self- test to ensure proper
operation. The modem also has four diagnostic 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 MultiModems 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).