The Development of a Handset for Telephone Stations

performance of the system. It is the object of this paper to discuss some of these problems and to describe their solution as embodied in the handset now being furnished by the Bell System. The idea of mounting a telephone transmitter and receiver on a common handle to form a handset was conceived early in the development of the telephone. In 1878, only a few years after the invention of the telephone, handsets of the type shown in Fig. 1 were in use by operators in the Gold and Stock exchange in New York City. Variable resistance transmitters of the Edison type were used in these handsets. This transmitter employed a relatively insensitive lamp black resistance element which was soon superseded by the more sensitive granular carbon type in order to permit the extension of telephone service to greater distances. The basic ideas underlying the variable resistance transmitter and the many advantages of granular carbon over the numerous other materials which have been tried have been discussed elsewhere. It is sufficient to point out here that the large amplification afforded at low cost by a well designed granular carbon transmitter makes it unlikely that any other structure will offer successful competition in general telephone application for some time to come. When an attempt was made to use granular carbon transmitters with handsets it soon became evident that a satisfactory design in1 2 1 2 in the design for general use of a handset which provides the MANY interesting development problems are presented convenience of this arrangement of a telephone set without a sacrifice in the * Presented at A.