GB191128165A - Improvements in Intercommunicating Telephone Systems. - Google Patents

Abstract

28,165. Fairweather, W., [Turner, K. M.]. Dec. 14. Intercommunication systems and apparatus.-In intercommunication systems in which there are two separate talking leads a<1>, a<2>, b<1>, b<2> &c., belonging to each station, there are provided at each station two contact bars 13, 14 connected to the jack contacts, one bar 14 being connected to the telephone instruments and the other bar 13 being normally connected to the switch hook contact 50, but being connected by the depression of the ringing key 17 to the lead o of the ringing battery. The circuit when station P<A> is calling station P<C> is from the lead o over contact 51 of ringing key 17, lead m<1>, bar 13, contact of plug C, lead c<2>, lead n<1> at station P<C>, and bell 33 back to the battery. The talking circuit is made from receiver R at station P<A> over lead l<2>, bar 14, contact of plug C, lead c<1>, lead l<1> at station P<C>, telephone instruments R, 23, switch hook 30, leads n' and c<2>, contact of plug C at station P<A>, and leads m<1> and m<2> back to the telephone instruments. The talking current is supplied from the leads t, t<1> by the inductances 34. In the arrangement of the station apparatus, Figs. 3 and 5, the transmitter 23 is mounted in spring clips 20, 21 and the jack springs 11 are arranged, as shown, to make contact with the bars 13, 14. A modified station apparatus is described, in which the jacks and plugs are replaced by keys and contact springs. The keys 112, Fig. 12, operate different sets of springs by movement in opposite directions, and are locked in operative position by a detent bar 120, catching in slots 116 and 117 in the keys and under the control of the switch hook. A frame on which the keys and springs are mounted is described.