NEC SV8100 User Manual page 6

Key Description,
To use the speaker option, you must have your MIC key on (will
Speaker
phone be red) to be able to talk back to the caller. Press MIC to turn on
and off. The MIC will also work as a mute key when using
speakerphone or handset.
Pressing the SPEAKER key will answer or release a call on
speakerphone.
If you already on call talking through the handset and you wish to
talk hands free, press the SPEAKER key, then replace handset.
NEC SV8100 Dterm User Guide
continued
6