Transducer Development for a Lightweight Operator's Head Telephone Set

A new lightweight operator's head telephone set is briefly described. The headset which weighs about 1/2 ounce is entirely supported by a custom-fitted molded plastic ear piece worn by the user. Contained in the headset are two small, electroacoustic transducers -- one for receiving and one for transmitting. The receiver delivers an acoustic signal into the user's ear canal through an ear insert. The transmitter is acoustically coupled to the user's lips by a speech tube and drives an amplifier which provides a proper voltage level for all Bell System applications of interest. Both transducers are variable reluctance, concentric pole designs.