"To scan only those talkgroups you have stored into your scanner, press SCAN while
scanning that system; or, press and hold TRUNK until the scanner displays READY TO
ID SCAN
. When one of the talkgroups you have stored becomes active, the scanner
switches to that transmission and displays the ID number and the alpha tag for that talk
group.
Note: You must store at least two talkgroup IDs in the system for ID scanning to work."
From page 24 in the pdf version of the manual