Clear and distinguishable for speech sound FSK/DTMF dual system auto switch 62 group Caller ID message memories 16 group outgoing message memories 3 group one-touch dialing memories 5 digit of local area code Flash tome 100/300/600/1000ms selectable Music on hold function 5 levels of LCD contrast adjustment 12 digits of number of incoming call display 15dB speakerphone volume control Ringer of outside and inside option function, incoming call indication In use indication RJ-11 and 2.5mm jack