Tom,

Here's what I found in the manual:

TONE FREQUENCY ID
This function scans through all tone frequencies to identify the incoming 
tone
frequency on a received signal. You can use this function to find which tone
frequency is required by your local repeater.
1 Press [TONE] to switch the Tone function ON.
· The icon appears on the display.
2 Press [F], [TONE] (1s) to run the Tone Frequency ID scan.
· The icon blinks and SCAN appears on the display.
· To reverse the scan direction, turn the Tuning control clockwise (upward 
scan) or
counterclockwise (downward scan).
· To quit the function, press [F] (ESC).
· When the tone frequency is identified, the identified frequency appears on 
the
display and blinks. Press any key other than the Tuning control while the 
identified
frequency is blinking, to resume scanning.
3 Press the Tuning control to program the identified frequency in place of 
the
currently set tone frequency.
· The Tone function will remain ON. You can press [TONE] to switch the Tone 
function OFF.
· Press [F] (ESC) if you do not want to program the identified frequency.

Steve