Hi Chip;
I'll add the following to rescue161's comments.
Here is some
background info on T4Win. T4Win will work find on most 800 and 900 mhz Type II systems but has been out of development for over two years.
For the present time, I suggest running
UniTrunker. It is more stable than T4Win and more accurate decoding (and more protocols too). When T4Win gets a much overdue facelift (and cranial transplant) - it will be running the UniTrunker decoding engine under the hood.
Historically, trunked radio decoding required a radio with discriminator audio. A few radios have this straight from the factory. For most models you must open the radio, locate the signal (pin "X" of chip "Y"), and install a "tap" to bring the signal outside the radio. Depending upon the software, you might also need an external circuit called a dataslicer that would allow using a spare serial port as a signal input into the computer. Other programs will use an audio input - like the microphone or line input. Once you get past this technical hurdle - decoding a whole range of trunking formats becomes possible.
The PRO-96 and 2096 are unique in providing the trunking data in packet form. Sadly, this is only done for P25 signalling. The PRO-96 / 2096 can be tapped. I think most folks prefer to tap a less expensive radio. Keep in mind that the radio providing disciminator audio need only tune to the control channel - it does not need to support trunking or digital audio.
If you want to tap your PRO-96 (or 2096) - you'll find plenty of help here and on the PRO-96 Yahoo! group.