Assistant type telephone set

Describes the desk and wall type eels developed jointly by Standard Elektrik Lorenz and Bell Telephone Manufacturing Company, and used by several European telephone administrations. The case is a copolymer of styrene and acrylonitrile. Miniature components are mounted on a printed-circuit board screwed to a metallic base plate fastened, to the case by screws. Only the bell and dial switch do not form part of the printed wiring. The circuits have been designed for improved performance on all existing feed lines connected to automatic or manual exchanges and to private branch exchanges. The handset dimensions correspond to recommendations of the CCITT. Response curves are given showing on overall response that compensates to some extent for the high-frequency losses of long subscriber lines.