That thing only uses two wires and a standard serial port. I gave mine up when I left the last site I worked at with NW8K. It shouldn't be too hard to make one if you know what wires go to what pins. You may have to use alligator clips to connect it to the zone sensor because you won't have the headphone jack connector.
The key to happiness is lower expectations.
Don't pick the fly crap out of the pepper.