The design of a new desk telephone for the Bell System began approximately in 1930, at the time of introduction of the 102 and 202-type desk telephones, which required two separate enclosures for the telephone circuitry and components. The existing Western Electric telephones used an external subscriber set ("subset"), containing the ringer and network circuitry, typically mounted on a wall or desk side. New concepts of design and economic efficiency emerged in Europe as well as in the independent market in the US in the 1920s, which combined all components of the telephone in one desk set unit. The model 302 was the first Western Electric telephone to include the ringer and network circuitry in the same desktop unit.