Is there a way to map, to a key, a windows operation? Disconnect dialup connection

[PingSpike]

I've got a headless machine that works as a file server. I want to use it as an internet gateway over a 56K modem. I have some software that disconnects when a call comes in like with call waiting, but I would like to be able to quickly disconnect the internet with a keystroke for making outbound calls, and also connect with a keystroke. (Although I could probably just have it do endless retry redial, but whatever)

Is there a piece of software that would let me reliably do this?