Another interruption that modems can get is if somebody else in the house picks up a phone connected to the same line as the modem.

If there is static on the phone line, this will cause the modems to not connect well. If you can hear audible static on the phone line that the modem uses then get the phone company to test the line.

Some other reasons for modems disconnecting are listed below.

The End User chooses to disconnect

This is the most obvious one. If the end user has chosen to disconnect, the PPP will drop the connection.

Idle Timed Out

Most ISP's have an idle time out. This means that if no activity occurs for x amount of minutes, you will get disconnected.

They loose the carrier signal

If a modem can not hear it's carrier signal for a certain period of time then the modems will disconnect from each other. This sometimes can happen because of Call Waiting as the call waiting beep stops the carrier. If the phone lines are having problems then that will also cause this problem. One thing you can do that will sometimes help stop this from happening is to type in the following setting into the Extra Settings box in the modem properties window.

S10=50

This setting will keep the modem connected for 5 seconds after it loses the carrier signal. The modem may be able to pick up the carrier signal again in that time. If the modems still keep disconnecting then you could try increasing the time. For example, if you wanted the modems to stay connected for 10 seconds then the setting would be - S10=100. The highest setting you can have is S10=254.

They have too many errors

If the modems receive too many errors whilst communicating, they will disconnect from each other

They have too many retrains / renegotiations

When a modem renegotiates a certain number of times it will then do a full retrain. If that modem retrains a certain number of times then it will actually disconnect.

Modem Hardware / Software Problems

One reason a modem may disconnect is when it has a physical problem. On a Win Modem, if the computers processor can't keep up with all it's processing then the modem may disconnect. The modems may also become disconnected if there is a bug in the software or firmware of either a Win Modem or a non-Win Modem.

Remote Jacks

This is a very rare situation, but if the phone line is connected through a special "remote jack" that plugs into the power outlet then this is most likely the reason for the problem.

SOLUTIONS TO TRY

Turn off compression

This makes the modems speak one less language to each other which in turn means there is one less thing that can go wrong. This solution will probably only cause a minimal bit of improvement however.

Change protocol

With most modems, except PCTel, changing the modem to K56Flex improves reliability. Be aware though that this will also have a natural tendency to slow the modem connection speed down.

Slow down the modem

Slowing down the modem is generally the thing that works the best. Some modems you only have to slow down slightly to get an acceptable reliability, others you have to drop right back dramatically. It is usually best to drop a modem back a fair amount first and then work your way up so that you get the reliable result first.

No modem is 100% reliable. The ratio of speed to reliability is a decision only you can really make. You could have it set to go slowly and disconnect hardly ever or you can have it set to connect fast but get disconnected more often. Whatever changes you make to the modem, the only way to really test to see if the problem has been solved is to   try the connection over a period of time.