Page 86, Radio Shack Pro 96 Owners manual:
Talkgroup ID Hold
You can set your scanner to follow a trunking signal that you want to track during scanning.
While the scanner is stopped on a voice channel (VC appears next to the frequency in the display), hold down Trunk until ID hold ON appears in the scanner's display.
To manually activate ID hold mode on a selected ID, enter the ID list, scroll to the desired ID, then press FUNC TRUNK. The scanner will initiate ID hold operation on the selected talkgroup.
When ID hold is activated and the scanner receives a voice channel, the scan indication S at the first digit in the top line changes to H to indicate the the call is being monitored while the scanner is in ID hold.
To release ID hold, press SCAN or TRUNK.