Once in a while in Windows, or DOS an older communications program may not release the modem when you disconnect from your dial up account, or you may get disconnected, then discover that there is no dial tone on your phone.
When this happens your modem still thinks it's supposed to be online, and you need to tell it to hang up the line. Fortunately, this is pretty simple to do.
If you are in Windows, go to Start, Run, and type in "command", then hit enter. This will give you a command prompt to work from in a DOS box.
The thing you will need to know now, is which com port your modem is using. It should be one of com1, com2, com3, or com4, sometimes other com ports, but not as often.
Within the DOS box, enter the command
Be sure to change com1 to whichever port your modem is using.
ath0 tells your modem to hang up, and the echo > sends that command to the com port your modem is using. Once the command has been typed in and you hit enter, your modem will hang up the line, and all will be well again.
This will of course work on a DOS based machine as well, if you're still running a dinosaur like that for some reason.
To look up which com port your modem is using, go to it's property sheets in Device Manager in Windows. Go to Start, Control Panel, System, and you will get the System Properties dialog.
Click the Device Manager button and you will get Device Manager.
In Device Manager select your modem, and right click it, then select Properties from the context menu.
You will get the modem properties dialog. Select the Modem tab, and near the top of it you will see the com port number assigned to your modem. Use this number with the ath0 command to shut down your modem.
