Modem Troubleshooting
Hundreds of modems are available on the market, all with their own peculiarities and idiosyncrasies. Some modems can present a challenge for the user. In order for the modem to perform correctly both modem hardware and modem software - the driver - need to be setup and configured properly.
Your modem hangs up every 5 to 20 minutes
This is a common problem when you have a fax machine or a telephone plugged into the same phone line as the modem. Try unplugging all other devices from the phone line, and testing to see if the problem still occurs.
Some cordless phones recharge its batteries for its recall memory by drawing electrical current from the phone line every 5 to 20 minutes. This is enough to interrupt high speed data transmission using a modem. To solve this you can either unplug the phone when you use your modem, buy a new phone, or if renting a phone from the telco, inquire if there is another model available.
Your modem disconnects unexpectedly
Telephone double adaptors and very long extension cables can cause drop-outs. Phone cables come in different qualities. If you are getting poor performance from the modem and a lot of drop-outs, good quality phone cable is worth investing in. If possible, try plugging the modem directly into the phone line with no other devices attached anywhere in the house.
If you have a digital mobile phone, telephony between such a phone and a GSM cellular base station can cause severe data transmission loss that can terminate a modem call.
If you have a burglar alarm which automatically dials and transmits data, this will affect your line quality. Ensure your modem communications are not carried out during alarms communication cycle.
Actually, anything electric can cause interference with your modem. Check what is turned on that is in close proximity of the phone line/modem. Things you might want to watch out for are TV's, radios, microwave, fridge (especially when it cycles on and off), washing machine going in to a spin cycle, air-conditioning cycles etc. Do you get a better connection when those things are off or on another power circuit? Try a surge protector. It protects the phone line as well as your modem power supply and power supply for your computer.
Other things that can create problems with modem drop-outs are poor waterproofing on the phone lines. Especially if the problem becomes more apparent when it is raining. Loose or old line wiring can also create noise on the line and disconnect you from the Internet. That copper wire, which runs around your house, down the street and to your local exchange can vary in quality. If it is in a poor state, nothing else you do will make any difference.
Modem cannot recognise the dial-tone
If your modem cannot recognise the dial-tone make sure that the phone line is plugged into the correct modem socket (usually: "Line"). Test the line to make sure that there is a dial-tone by plugging a telephone into the same socket. Try to make a call from it.
If you have Telco voice mail you will hear a different beeping dial-tone. Your modem will not recognise it as a dial-tone and you will not be able to dial out.
You can change settings on your computer to ignore dial-tone and dial regardless. In Windows95/98 untick the option "wait for dial tone before dialing" in your modem properties. In Macintosh tick "Ignore the dial tone" in your dialler or modem properties. You can also try adding x3 to your modem initialisation string.
As soon PPP/SLIP starts, everything stops
Check that you have hardware flow control, and a modem cable that supports this. In Windows95/98 you can go to Control Panel, then Modems, choose Properties under the modem you are using. Click on Connection tab then the Advanced button and choose Use Flow Control: Hardware(RTS/CTS) In a Macintosh check your modem properties in the ppp software you are using to connect.
Modem connection shows some huge amount like 57600 or 115200 - what's happening?
Your modem has been setup to show the port speed, which can be changed in modem properties on your system. It is reporting the speed between your modem and your computer instead of the speed between your modem and the ISP. To show the actual connection speed add w2 to your initialisation string.
With a 56K modem: after a while connection stops for a few moments, or hangs up completely
56K modems push the phone line to the limit, and need to "retrain" (that means change speed) regularly to keep up with the line conditions. It takes a few seconds to do this retraining, and these are the pauses you may experience.
Sometimes, when the retraining occurs, it can't successfully negotiate a new speed and will hang up.
As this problem becomes more pronounced the faster your modem runs, if you are experiencing difficulties it may be wise to "lock" your modem at a certain speed. First try intermediate speeds such as 44kbps, 40kbps etc. Failing all else, turn off K56Flex/V90 in your modem all together and connect with 33.6kbps.
Check your modem manual for instructions on how to do this, or try something like this in your init string:
For 56k flex modems try:
Forcing 44kbps: +ms=56,1,1200,44000
Forcing 42kbps: +ms=56,1,1200,42000
Forcing 40kbps: +ms=56,1,1200,40000
For 56k V90 modems try:
Forcing 44kbps: +ms=12,1,1200,44000
Forcing 42kbps: +ms=12,1,1200,42667
Forcing 38kbps: +ms=12,1,1200,38000
If your modem has problems accepting the above strings, try:
Forcing 44kbps: +ms=v90,1,1200,44000
Forcing 42kbps: +ms=v90,1,1200,42667
Forcing 38kbps: +ms=v90,1,1200,38000
And so forth, down to:
Forcing 33.6kbps: +ms=11,1,1200,33600
If your modem has problems accepting the above string, try:
Forcing 33.6kbps: +ms=v34,1,1200,33600
If the strings above do not work with your modem, please refer user to modem's manual.
To add an initialisation string on Windows95/98 go to Control Panel and Modems, choose your modem and go to Properties. Click on Connection tab then Advanced button. Extra settings is where you need to type the string.
On Macs, only freePPP dialler will allow you to change the initialisation string. In the OTppp software, to include an initialisation string, you need to generate a modem script. In Open Transport PPP software you should make sure you are using a script supplied with your modem.
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