I don't see the PRO-91 radio in our "list"
here is a link to what we Do support
The radio is "ancient". Being that it was probably the very first computer programmable Trunking radio RadioShack ever made. (Early 1990's)
It most likely uses the Headphone jack for the programming cable, and if that is so, unless you have a real Serial Port on your compute,
it is not possible to get anything to work due to the way those old cables were made.
New, USB programming cables such as the 20-546 cable< won't work either.
Here's a short FAQ on all the reasons why it probably won't work even if you HAVE Software
My Personal recommendation is not to spend a lot of time and money on the radio,
as there are newer radios that will work better, receive more etc,
and end up costing you little more that trying to get "yours" to work.
I have a Radio Shack PRO-91 Scanner.
Will your current Scan-Cat Lite work with this scanner? I have the correct cable,
but lost the older version of the software in a computer failure. Know where I can get the software?
No virus found in this message.