See also:

Conference Call
When two calls are in progress (one active and one on hold), press and hold the button until you hear a double beep indicating that the two calls have been joined into one conference call. ...

Place/Retrieve A Call From Hold
To put a call on hold, press the button until you hear a single beep. This indicates that the call is on hold. To bring the call back from hold, press and hold the button until you hear a s ...

TIME Button (Auxiliary Mode)
Press this button to change the display to time of day. The time of day will display for five seconds (when the ignition is OFF). ...