During a Conference Call these are features Participants and Moderators can use by entering the corresponding keys into their phone:
Play menu of features
This lets the caller know which features are available to them via the telephone.
Mute your own line
This mutes the callers line so other participants in the conference can not hear him.
Unmute your own line
This Unmutes the callers line so other participants in the conference can hear him.
Hear number of participants
This tells the caller the number of participants currently in the conference.
Lock
This locks the conference so no other callers can get in.
Unlock
This unlocks the conference so more participants can join.
Mute All
This mutes the conference. This is a toggle feature. If you press it once, the callers can unmute themselves. If you press it twice, the callers can not unmute themselves.
Unmute All
This unmutes all participants.