Chapter 5 – Troubleshooting
MT9234ZBA-USB-CDC-XR User Guide
20
The Modem Doesn’t Work with Caller ID
●
Caller ID information is transmitted between the first and second rings, so if autoanswer is turned off (
S0=0
)
or if the modem is set to answer after only one ring (
S0=1
), the modem does not receive Caller ID information.
Check your initialization string, and if necessary change it to set the modem to answer after the second ring
(
S0=2
).
●
Make sure that you have Caller ID service from your telephone company.
Fax and Data Software Can’t Run at the Same Time
Only one application at a time can access communications devices. In Windows 2003 and later, you can have data and fax
communication applications open at the same time, but they cannot use the same modem at the same time.
The Modem Dials But Cannot Connect
There can be several reasons the modem fails to make a connection. Possibilities 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.
You can narrow the list of possibilities by using extended result codes. Extended result codes are enabled by
default. If they have been disabled, enter
ATV1X4
and press Enter while in terminal mode, or include
V1X4
in the
modem’s initialization string. 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, plug a telephone into your modem’s telephone wall jack and listen for a dial tone. If you hear a
dial tone, your modem might be installed behind a company 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 your PBX 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 causes 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, in which case you should try again later, or it
might indicate that you have 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 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 98 HyperTerminal, select
Call
from the
Call
menu, click
Dialing
Properties
, and type
9
in the local and long distance boxes in
How I dial from this location
.
●
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.
