86
MINI-MODEM V.92
9.1.3 T
HE
M
ODEM
C
ANNOT
C
ONNECT
W
HEN
D
IALING
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.
• 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
ENTER
. 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 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 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
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, 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 (for example, ATDT9,). Note the comma, which
inserts a pause before the number is dialed. By inserting 9, into the dial prefix,