The dry cell has almost completely replaced the wet cell in this country, and as a result, the general type of wall set as shown in Figs. 142 and 143, has gradually replaced the old wet-cell type, which was more cumbrous and unsightly. It is usual on wall sets to provide some sort of a shelf, as indicated in Fig. 142, for the convenience of the user in making notes and memoranda.

Desk. In the magneto desk-telephone sets, the so-called desk stand, containing the transmitter, the receiver, and the hook switch, with the standard upon which they are mounted, is shown in Fig. 144. This desk stand evidently does not comprise the complete equipment for a magneto desk-telephone set, since the generator, polarized bell, and battery are lacking. The generator and bell are usually mounted together in a box, either on the under side of the desk of the user or on the wall within easy reach of his chair. Connections are made between the apparatus in the desk stand proper and the battery, generator, and bell by means of flexible conducting cords, these carrying a plurality of conductors, as required by the particular circuit of the telephone in question. Such a complete magneto desk-telephone set is shown in Fig. 145, this being one of the types manufactured by the Stromberg-Carlson Manufacturing Company.

Fig. 144. Desk Stand
[View full size illustration.]

A great variety of arrangements of the various parts of magneto desk-telephone apparatus is employed in practice. Sometimes, as shown in Fig. 145, the magneto bell box is equipped with binding posts for terminating all of the conductors in the cord, the line wires also running to some of these binding posts.

In the magneto-telephone set illustrated the box is made large enough to accommodate only the generator and call bell, and the batteries are mounted elsewhere, as in a drawer of the desk, while in other cases there is no other equipment but that shown in the cut, the batteries being mounted within the magneto bell box itself. In still other cases, the polarized bell is contained in one box, the generator in another, the batteries in the drawer of the desk, the induction coil being mounted either in the base of the desk stand, in the bell box, or in the generator box. In such cases all of the circuits of the various scattered parts are wired to a terminal strip, located at some convenient point, this strip containing terminals for all the wires leading from the various parts and for the line wires themselves. By combining the various wires on the terminals of this terminal strip, the complete circuits of the telephone are built up. In still other cases the induction coil is mounted on the terminal strip and separate wires or sets of wires are run to the polarized bell and generator, to the desk stand itself, and to the batteries. These various arrangements are subject largely to the desire or personal ideas of the manufacturer or user. All of them work on the same principle so far as the operation of the talking and signaling circuits is concerned.

Fig. 145. Magneto Desk Set
[View full size illustration.]