Where as I do not know of any such device on the market I do know how to build one.. I'd have to do some research but it's a published article, You just need to make one small change.
If you can find one that turns on a light, either a regualr bulb or an LED (Led is best) replace the LED with an opto isolator,,, and use it to control a pizo buzzer, job done.
NOTE: This is how I key my ham radio on occasion,, Computer activates and LED, opto-isolator keys the radio, that way there is no ELECTRICAL connection between the two.
