of noises including ascending tones or chiming sounds. This calibration may be automatic or manually invoked by the user, and it may need to be repeated if the speakerphone is relocated within the room. A failure to be properly calibrated can be indicated by the occurrence of echoing, ringing sounds, or feedback. Handset vs. base speakerphone Many cordless telephones have a handset speakerphone as well as a base speakerphone. The handset speakerphone allows hands free conversations away from the base unit. The base speakerphone is located in the base unit. The user must be at the base unit, but still gets the added benefits of having hands free conversations. Most base speakerphones have a secondary keypad for dialing calls on the base unit. See also Loudspeaker References Telephony equipment