Modem dial-tone does not stop

I am using NT 4.0 and have the AOpen FM56-ITU/2 modem installed. The telephone line is connected to the modem and the other end to the phone jack. There is a constant dial-tone. When I go to dial out, I get a voice recording that says "exceeded time to dial" and then a hardware error message on the screen. So far the only way to keep this from happening is to unplug the phone line and only plug it in when I am ready to dial out. However, the phone jack is in an awkward place. I have to either bring up the dial screen first, run over and plug the line in, run back and press dial before getting the messages, or have someone stand at the phone jack and kind of plug it in while I simultaneously begin the dial process. Anyone have any idea how to better this situation? I was wondering if there was a way to keep the line plugged in, but turn off dial from the computer program and just turn it back on when I am ready. Thanks for any help.