Was able to obtain the parts for an EMWIN 1200 Baud modem from EBay (in the case of the TCM3105JL chip) and from Newark Electronics for the MAX232ACPE. Other parts can be obtained from Radio Shack, Newark and Mouser Electronics. A link to the schematic is shown below:
(Xenocode DM-201B demodulator)
The total cost for the modem was under $20. The circuit was first built on a breadboard and tested with several software packages. It works quite well using the discriminator outputs from both PRO-2005 and PRO-2041 scanners. The discriminator signal output from a BCD996T is too low to adequately drive the circuit. Audio output into the modem will also work just fine.