How to reboot a computer through a phone-call?

Hello,

I am using PcAnywhere via the internet on a remote machine and sometimes it happens that the connection gets hung up and the whole computer freezes.  The only solution is to manually reboot the computer (which re-opens PcAnywhere again).

My idea:
If I hooked up a special modem/hardware-box to that computer and to a phoneline then I could make a phonecall to this hardware-box, possibly type in an authorization code and the hardware-box would interrupt and restore the power-supply to the computer, which would force the machine to reboot. (It's a DOS-machine that I connect to through SPX network), so no keypresses necessary after reboot).

My question:
Does such a modem/hardware-box exist?  All it should do basically is to control the power-supply to a computer and cut it off if it is called by phone.

Thank you for your advice.

Kind regards
Reinhard