GB459198A - Improvements in or relating to operators' sets for telephone systems - Google Patents

Abstract

459,198. Exchange systems. TELEPHONE MANUFACTURING CO., Ltd., Martell Road, West Dulwich, London, FLINT, J. G., Kenlyn, Station Road, Orpington, Kent, and RYALL, L. E., 9, Lowlands Road, Eastcote, Pinner, Middlesex. Aug. 29, 1935, No. 24189. [Class 40 (iv)] An exchange operator is provided with a loudspeaking telephone set in addition to or in place of the ordinary set, amplifying equipment being associated with the set itself or with the cord or other exchange connecting circuit. The invention is primarily applicable to systems employing a single operator but may be used where several operators are employed if they are not close together. An ordinary microphone may, however, be used for speaking. In the arrangement shown, suitable for systems in which the subscribers have individual amplifiers for loud-speaking sets or in which loud-speaking facilities are not provided, the operator's loud-speaker LS and microphone M are associated with amplifiers AM, BM connected over a hybrid coil to the speaking key K. By using the twoway amplifying arrangements described in Specification 415,767, 416,372, 430,158, or 430,567, the hybrid coil may be dispensed with, and arrangements may be provided to prevent room noise from exercising control. As applied to the amplifying cord circuit described with reference to Fig. 2 of Specification 445,860 which provides for connecting one loud speaking substation to another or to an ordinary substation, the operator's ordinary set and the attenuating pad therefor are replaced by a loud-speaking set. The loud-speaker and microphone, in this case, may be connected up in series or parallel or over a hybrid coil, or to separate windings of a transformer, or the loud-speaker may be connected in series with the secondary of a microphone transformer. Alternatively, the directional switching arrangements described in Specification 444,598 may be used if the operator is subjected to steady background noise. Moving coil or other high quality microphones may be used.