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.