Technical Support: Modem Troubleshooting Help (Dial-Up)
When your modem hangs up without warning:
When this happens, its called a "dropout". There are many possible causes of a dropout, and unfortunately its a fact of life that analogue modem technology is not the most reliable thing in the world and no matter what you do, there is still a chance that the public telephone network won't quite be able to hold a high speed connection. If you are experiencing them regularly however, there are some things you can do to help minimise the risk of experiencing a dropout.
Call waiting
The first and most simple thing to check and fix if you are experiencing dropouts regularly is call waiting. If you have call waiting (which many people in fact do without realising it.. it is now a free service which may have been added to your phone service whether you have asked for it or not) and it is switched on, different modems can react to an incoming call in different ways depending on the circumstances.
Some will soldier on unaffected, some will need to re-train down (ie. Renegotiate at a slower speed thus making you connection slower) and some will hang up. Just because a given modem normally carries on unaffected doesn't mean it always will. As a general rule, it is best to switch off call waiting while you are using your modem.
Solution: To switch off call waiting, pick up the handset on your phone and dial #43#. You will received a message saying that call waiting is off (if you have it) and you can then hang up. To switch call waiting back on when you are finished with your modem, pick up the phone and dial *43#. You should received a message saying call waiting is on.
Other devices on the same phone line
The other big cause of dropouts is having another phone device on the same phone line while you are using your modem. Telstra T-200 model phones are the biggest offenders but are by no means the only ones. It is important to note that it is irrelevant how other phone devices are connected in your house, they can still have an effect.
If there is a phone, fax machine, another modem, answering machine or line sharer (or any other device at all) plugged into a double adaptor, a different phone socket somewhere else in the house, plugged into the modem in serial or otherwise connected in any way whatsoever, there is a chance it will disrupt your modem's operation.
The only case where you can be assured there will be no possible effect is if you have more than one phone service (ie. More than one phone number), devices plugged into sockets which are dedicated to a different phone number to the one which the modem is plugged into should have no effect on the separate line. Many people don't have to worry about other phone devices causing dropouts, their line can be loaded up with all sorts of phone devices and they won't have any problems at all.
It all depends on a multitude of factors and on occasion you may find that even though your modem has been running fine for a while, if it suddenly starts experiencing dropouts, removal of the phone devices which didn't cause a problem before can fix the problem.
Solution: Remove all other phone devices while using the modem.
Dialling through a PABX
It is quite possible to use your modem to connect to the Internet through a PABX. This is however, not an entirely desirable situation. Generally, all that is required to dial through a PABX is to put the lead number required for an outside line (usually 0) followed by a comma before the number you are dialling. Eg. to connect to our sydney digital bank you would put in your modem dialler as the number to dial: 0,90110000 The problem with dialling through a PABX is that connect speeds will often be lower than normal and chances of dropouts are greatly increased.
Some modem/PABX combinations will work better than others, unfortunately the diversity of makes and models of both modems and PABXs means there is no definitive source of information on how well combinations will work.
Solution: Don't dial through a PABX if you can avoid it! If you have no choice and are having problems, try different a different modem.
There are certain things you can do to harden your connection when you have no choice but to dial through a PABX or you have already tried the other things mentioned so far and are still experiencing regular dropouts.
Modem drivers
With modern operating systems you are required to use a modem driver which tells your computer how best to communicate with your modem. The operating system will probably come with built in standard modem drivers as well as drivers for many different makes and models of modems. A lot of modems also come with their own drivers on a disk when you buy them now days.
Often modem drivers are quite similar and there can be several which will work for a given modem. At the same time, some drivers will not work particularly well for a given modem. In some cases even the driver which comes with the modem may not be the best one for it. The effect of modem drivers on the way your computer talks to your modem and thus the way that your modem works usually has more bearing on the way that your modem negotiates a connection, but it can also have an impact on how effectively the modem will hold a connection.
As touched on above the modem drivers which you are likely to be using could fall into 4 different categories : The Standard modem driver which comes with your operating system, a modem driver specifically for your modem or a model similar to your modem which has come with the operating system, a driver which came on a floppy disk with the modem when you bought it, or a driver for your modem which you have downloaded from the Internet. Any one of these is valid, but if you are having modem problems (regular dropouts or failures to negotiate) its probably worthwhile to try a different one to the one you are currently using.
Turning down modem speed
Another options is to turn down the port speed or connection speed of your modem. This is unlikely to make your connection noticeably slower in most cases, but can make the connection more stable.
If you are using Windows95/98 Dial-up Networking to connect... Go My Computer, Dial-up Networking, Right click on the connection icon for your connection and select Properties from the drop-down menu. Then click the Configure button, and on the General tab (which should come up by default) you will see a Maximum Speed setting. Click on this to change it. 38400 is generally the best trade off between speed and stability, but don't be afraid to try others if things aren't working out.
If you are using Trumpet Winsock... Go to the File menu (in Trumpet Winsock) and select Setup. In the field entitled Baud Rate (or similar) change the setting to 38400 (if it isn't that already).
Faulty modem
The last straw when you have eliminated all other possibilities is to put it down to the modem being damaged in some way. It is rare to find a new modem these days which will not communicate effectively and in a stable manner with other modems straight out of the box - or failing that, after the above steps for eliminating possible causes of problems and appropriate steps to harden the connection have been taken.
Most reputable modem retailers will be happy to exchange your modem for another of the same make and model, and if the brand you have purchased turns out to be a really bad one, some may be prepared to let you negotiate a deal for a different modem altogether.
Fax: (02) 8088 7949