NP Troubleshooting Guide
Updated 30
May 2002
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1. Is it plugged into the phone jack?
2. Is the external modem plugged into the computer? Is
the connection solid?
3. There are two jacks on a modem. Are the lines
reversed?
4. Is the phone line working? Plug in a phone. Is there
a dial tone?
5. Do you need to dial an extra character to get an
outside line, such as 9or8?
6. Has the modem ever worked, or is this a new
installation? If it is a new installation, check these things:
* Is
the modem set to the same COM port and IRQ that the software is set to?
* Is
another device also configured to the same COM port or IRQ that the modem is
using?
* For
an internal modem, check the DIP switches and jumpers (if available). Do they
agree with the modem properties in the OS?
* Try
moving an internal modem to a different expansion slot. For an external modem
using a serial port card, move the serial port card to a different slot (This
may do only in older systems).
* For
an external modem, use a different serial cable.
* Did
the software correctly initialize the modem? If you did not give the correct
modem type to the software, it may be trying to send the wrong initialization
command. Try AT&F. (Under Windows 95, click Start, Settings,
Control Panel, Modem. Select the modem and click Modem Properties, Connections,
Advanced Connection Settings. Enter the AT command under Extra settings(see NP fig1). Retry the modem.
* Is
the computer short on RAM or hard drive space? Try closing all other
applications currently running.
The Modem says there is no dial tone, even though you
can hear it
1. The
modem may not be able to detect the dial tone even if you can hear it. Try
unplugging any other equipment plugged into this same phone line, such as a Fax
machine.
2. Try
giving the ATX0 command before you dial. Enter the command under Advance
Settings, as in NP fig1.
3.
Straighten your phone lines! Don't let them get all twisted and crossed up with
other heavy electrical lines.
The Modem dials and then says that the other end is
busy, even when you know that it is not
1.
This can happen with international calls; the modem does not recognize the
signal as a ring. Try giving the ATX0 command first.
2.
Straighten the phone lines and remove extra equipment, as described above.
The sending modem and the receiving modem take a very
long time to negotiate the connection
1.
This is probably because of a noisy phone line. Try calling again or using a
different number.
2.
Remove other equipment from your line. A likely suspect is a credit card
machine.
3. Try
turning off data compression and try again.
4.
Turn off error correction and try again.
5. Try
forcing your modem to use a slower speed.
During a connection, it sounds as if the handshaking
starts all over again
Modems normally do this if the phone line is noisy and
causes much data to become corrupted; it's called retraining, and it sometimes can solve the problem as the modems
renegotiate, compensating for the noisy line. Do the things listed above to
clear your line of equipment and twisted phone lines.
Does your modem support data compression? Check that the
modem is configured for it.
1.
Check the communications software for the speed assigned to it. Many times
people set the communications software speed for the modem speed instead of for
what the software is asking for, the port speed, which should be about four
times the modem speed.
2. You
may have a noisy phone line. Try the connection using two modems of the same
brand and model. If performance is better, the problem is most likely the phone
line.
3. Is
the phone line from the modem to the jack too long? About 4 feet is the limit;
otherwise, electromagnetic interference may be the problem.
4.
Straighten the phone lines and clear the line of any extra equipment.
5.
Reinstall the modem. Allow Windows 95 to detect the modem for you and install
its own drivers.
The Modem drops the connection and gives the NO CARRIER
message
1.
Most likely the connection was first dropped by the remote modem. Is someone
trying to use a phone extension on this line?
2.
Disable call waiting. To do this, put *70, before the dialing number. Some
communications software has a setting to disable call waiting. If not, you can
put these four characters in Extra Settings box of Advanced Connections
Settings (see NP fig1).
3. Remove extra equipment from the line and straighten
the phone lines.
Whenever the weather is bad, the connection disconnects
often
This is caused by a dirty phone line. Does your line
make extra noises at these times? Remove any extra equipment and straighten the
lines.
Whenever large files are downloaded, some of data is
lost
Make sure that hardware flow control is on, and that
software flow control is off, for the software, the COM port, and the modem.
The connection fails whenever large files are uploaded
or downloaded
There may be a buffer overflow. Try these things to gain
better control of data flow:
1.
Make sure that hardware flow control is on, and that software flow control is
off, for the software, the COM port, and the modem.
2. Is
the serial port speed set too high for the UART chip you have? Lower the port
speed.
3. For
an external modem, try a different serial port cable.
1.
Check the port settings. Try 8 data bits, no parity, and one stop bit (8, No,
and 1).
2. Slow down the port speed.
3. Slow down the modem speed
