Ringer box

In telephony, ringer boxes and similar devices are often categorized as subscriber sets.

Ringers were commonly placed in the same housing as the subscriber set, which consisted of other electrical components, such as induction coils, capacitors, and, if required, a magneto generator.

The electromagnet of the clapper responds to the alternating current sent from a central office exchange or another phone via the telephone network wiring.

Ringer boxes were produced by all manufacturers of customer-premises telephone equipment.

In North America, the prominent producers were Western Electric, Automatic Electric, and Kellogg Switchboard & Supply Company, while in Europe companies such as Siemens & Halske and Ericsson mass-produced devices.

Western Electric hand telephone set of c. 1930 with its ringer box or subscriber set in the background.
Western Electric common battery subscriber set of c. 1930, containing a bell ringer, an induction coil, and a condenser, mounted underneath the wooden connecting board.