i am working on this for a friend. i actually have a pro 96. he is giving me a bd796d for fixing it for him so that is pretty cool. so as of now i have no cables to program with unless the cable from the pro 96 will work havent tried yet.
Most of the pre-programmed systems on the 996T are ancient and probably no longer "work". So rather than locking them out, I'd suggest deletion. That would free up memory in the scanner.
If you are using a computer with a Windows operating system previous to 8.0, you could get a Uniden USB-1 cable. That cable will connect to a USB port on your computer to the front port on the scanner.
You can the use any of the following software programs to program the scanner, to include deletion of the pre-programmed systems: Uniden's USAD (Free), FreeScan (Free), ARC 996 (cost) or ProScan (Free demo, then cost).