Redial; Mute - Cisco SPA 504G Owner's Manual

(Except phones set to DND or phones in use)
5. Hang up the phone when finished.

Redial

The Redial function places a call to the last number dialed. To use the
Redial function, use the redial soft key.

Mute

The mute feature allows you to hear the other party, but they cannot
hear you.
During a call, press
the screen indicates that the other party (or parties) cannot hear you.
Microphone Mute applies to all modes: Handset, Headset, and Hands-free
Speakerphone. You can still hear all other parties while mute is enabled.
To turn off Microphone Mute, press
24
. The button turns red and a microphone on
again.