This mode decodes several types of tones which are commonly heard on the VHF/UHF bands.
 
These buttons select which type of tone to decode:
DTMF (“Touch Tone” which is probably a trademark of the telephone company)
EIA
CCIR
XPH tones
The decoded digits are displayed in the text window.
(XPH is a spy numbers station that sends messages via tones, rather than voice or morse code. It is believed to be operated by a Russian intelligence organization)