Kevin,
For uniden models, there are 2 different cables. One is RS232 (serial) and the other is USB (prolific rs232 integrated serial adapter---not compatible with Windows 8).
Once connected you use Freescan to create the channel list and write to the scanner.
For Mitchell County here is the way you want to program your scanner:
Create system, call it Viper
Create site, if you are on South End use Woodys Knob tower
On north end, use Locust Knob.
Create groups with the talk groups you are interested in monitoring.
On the scanner, you can do ID Scan or ID Search. Scan allows you to monitor only the channels you have inputted, while ID Search allows you to monitor all feeds from the tower. Sometimes this can be good or bad. For us monitoring Woodys Knob, this can be bad as a lot of Burke County radios are affiliated and get served off this tower. The bad part is, if you are listening to a transmission from Burke county and something gets transmitted for the home area, you will miss the home area transmission. Nonetheless this a mode you can change simply by pressing the Scan button on the keypad.
Also, if you have an older analog scanner, I would recommend that you continue using it to pick up VHF channels instead of trying to monitor viper and the old VHF frequencies on the same scanner.