Tait TM9480 User Manual page 18

About the keypad microphone
18 Getting started
Your radio may have a keypad microphone installed.
The keypad microphone has a PTT key as well as
alphanumeric keys, two scroll keys, and left and right
selection keys.
The PTT key, the scroll keys and the selection keys all
work in the same way as those on the radio control
head (see "About the radio
microphone
PTT key
(press-to-talk)
left selection
key
controls").
alphanumeric
keys
right selection
key
scroll keys