Usage

Speaker phone mode is not attached to a particular call but to a particular major handset. So this mode can be activated even no call is handled by the handset.

When a handset is on speaker phone mode, not only the call but also all sounds associated with the handset are played on device(s) configured to be used in speaker phone mode.

Only one major handset can be on speakerphone mode at the same time. So activating speaker phone mode on handset two while it is already activated on handset one cause the feature to be deactivated on handset one.