Section 4 - Troubleshooting; The Modem Does Not Respond To Commands; The Modem Dials But Does Not Connect; The Modem Does Not Dial, Reporting "No Dialtone - Mitsubishi Electric A2S-MODEM User Handbook Manual

Section 4 – Troubleshooting
Your modem is designed to provide reliable and trouble free functionality. However,
should you experience any difficulty, the information in this section may assist you in
determining and resolving the source of the problem. If you cannot resolve your
situation after reading this chapter, contact your dealer of the Technical Support
Centre at the number provided on the last page of this manual.

4.1 The modem does not respond to commands

1. Ensure that the PC is not configured to a conflicting COM port and/or IRQ
setting. Your modem cannot be connected to a COM port currently in use by
another device in your system (e.g. mouse). Similarly IRQ settings must not
overlap.
2. Make sure that the communication software is configured with the correct COM
and IRQ settings (i.e. the same as the modem). Your communication software
will not be able to send or receive data if it is not configured to match the COM
settings of the modem
3. Check that the modem is not configured to echo off or command reporting off.
This can be done by typing the commands ATE1 to restore echo and ATQ0 to
restore command reporting. By default, the modem will be set to echo off and
reporting off.
4. The modem will not respond to commands if Dial On Demand is enabled, for the
first ten seconds after power up.

4.2 The Modem Dials but Does Not Connect

1. The best method of diagnosing this kind of problem is always to connect a
suitable head or handset to the modem as it is dialling.
2. Check that you are dialling the right number.
3. Check that the remote modem has the correct line cable connected.
4. If the remote site keeps ringing without picking up, it may either be unplugged or
it has not been programmed to auto-answer.
command ATS0=1 instructs auto answer after 1 ring.
5. Check that the line connected to the remote modem is not part of a digital mini-
exchange, this type of system requires an analogue (2-wire) adapter.

4.3 The Modem Does Not Dial, Reporting "NO DIALTONE"

Problems of this type are almost always due to the telephone cable/connection.
1. Check that the telephone cable is connected correctly to the modem and phone
socket.
2. Check that the cable used is the correct type for the country you are in, the one
supplied is only suitable for connection in the UK. Line connections are delivered
on pins 3 & 4 of the line socket.
Setting the modem with the
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