Chapter 4 - Troubleshooting
Multi-Tech Systems, Inc. MT9234ZPX User Guide
45
The
Modem
Cannot
Connect
When
Dialing
Reasons why the MultiModem may fail to connect include:
●
lack of a physical connection to the telephone line.
●
a wrong dial tone.
●
a busy signal.
●
a wrong number.
●
no modem at the other end.
●
a faulty modem, computer, or software at the other end.
●
incompatibility between modems
●
poor line conditions.
You can narrow the list of possibilities by using extended result codes. Extended result codes are enabled by
default. If they have been disabled, include
V1X4
in the modem’s initialization string, or in terminal mode enter
ATV1X4
and press E
NTER
. When you dial again, the modem reports the call’s progress.
●
If the modem reports
NO DIALTONE
, check that the modem’s telephone line cable is connected to both the
modem’s LINE jack (not the PHONE jack) and the telephone wall jack. If the cable looks secure, try
replacing it.
If that doesn’t work, the problem might be in your building’s telephone installation. To test the building
installation, check for a dial tone by connecting a standard telephone set to the line in place of the modem.
If you hear a dial tone, your modem might be installed behind a corporate phone system (PBX) with an
internal dial tone that sounds different from the normal dial tone. In that case, the modem might not
recognize the dial tone and might treat it as an error. Check with your PBX personnel or the PBX system
manual to see if you can change the internal dial tone. If you can’t, change your modem’s initialization
string to replace
X4
with
X3
, which will cause the modem to ignore dial tones (note, however,
that
X3
is not
allowed in some countries, such as France and Spain).
●
If the modem reports BUSY, the other number might be busy. Try again later. BUSY can also indicate that
you failed to add a
9,
prefix to the phone number if you must dial
9
for an outside line.
If you must dial
9
to get an outside line, the easiest way to dial it automatically using legacy software is to
include it in the modem’s dial prefix, e.g.,
ATDT9,
. Note the comma, which inserts a pause before the
number is dialed. By inserting
9,
into the dial prefix, you do not have to include it in each directory entry.
To change the dial prefix in Windows HyperTerminal, select
Connect
from the
Call
menu, click
Dialing
Properties
, and type
9
in the local and long distance boxes.
●
If the modem reports
NO ANSWER
, the other system has failed to go off-hook, or you might have dialed a
wrong number. Check the number.
●
If the modem reports
NO CARRIER
, the phone was answered at the other end, but no connection was
made. You might have dialed a wrong number, and a person answered instead of a computer, or you might
have dialed the correct number but the other computer or software was turned off or faulty. Check the
number and try again, or try calling another system to make sure your modem is working. Also, try calling
the number on your telephone. If you hear harsh sounds, then there is a modem at the other end. In that
case, the modems might be having problems negotiating because of incompatibilities or line noise. Try the
call again, connecting at a lower speed by setting register S37 to a lower rate (for example, by typing
ATS37=11
in the terminal window and pressing E
NTER
).
●
Poor line conditions can also affect the connection. When using V.34 or V.32 client-to-client connections in
poor conditions, setting
S38=0
may result in better performance.
