Multi-Tech Systems MT5600ZDX ユーザーズマニュアル

1. Connect the modem to your computer. Using your communication program, set

the desired baud rate and go into terminal mode.

2. Type AT and press E

NTER

; you should get an OK message. Type AT\N and press

E

NTER

 to disable error correction.

3. Type AT&T1 and press E

NTER

. This places your modem in analog loopback

mode in the originate mode. A CONNECT message should appear on your
display. The modem is now out of command mode and in a pseudo-online
mode.

4. Note that the CD indicator is on. If it is not on, there could be a problem with

your modem.

5. Enter characters from your keyboard. For this test, typing multiple uppercase U

characters is a good way to send an alternating test pattern of binary ones and
zeros. The characters entered should be displayed on your monitor.

6. To exit the test, type the escape sequence +++AT and press E

NTER

. This puts the

modem in online command mode. Then type either AT&T or ATH to return to
command mode.

7. Your modem passes this test if the data received on your monitor is the same as

the data entered from your keyboard. If different data appears on your monitor,
your modem is probably causing the problem, though it could also be your
computer. If your modem passes this test, but you are receiving errors while on
line, the remote modem or the phone line could be at fault.

The remote digital loopback test tests the phone lines and the circuits of both your
modem and a remote modem. In this test, your modem must be on line with another
modem that is set up to respond to a request for remote digital loopback. (Note that
some modems might not support remote digital loopback or might have it disabled.)
Data from your computer or terminal is transmitted through your modem and over
the phone line to the remote modem, where it is then looped back to your modem.

Figure C–2. Remote digital loopback test.