GB328324A - Improvements in or relating to call recording apparatus for use in telephone systems - Google Patents

Abstract

328,324. Pollak, J. E., (Associated Telephone & Telegraph Co.). Jan. 26, 1929. Automatic exchange systems.-A subscriber on 'leaving his telephone may operate a switch 1 to connect apparatus to the line by means of which a record of the incoming calls is made on a paper strip under the control of impulses dialled by the calling party and repeated at the exchange. When the line is called, ringing current from the exchange passes through relay 5, which attracts its light armature 9 and shunts condenser 7 in its circuit, thus simulating the reply of the subscriber, whereupon the ringing current is replaced by direct current and relay 5 energizes fully and attracts armature 10, which releases gear-wheel 32, strikes armature 9 and engages a locking pawl 38 so that both armatures are held operated independently of relay 5. Wheels 32, 33, 34 and 31 and the paper feed rollers are geared together, and the pair of wheels 31, 32 make a revolution in the same time, while wheel 34 rotates rapidly and by intermittent short-circuiting at contacts 22, 23 of coil 20 in the line circuit sends back an audible tone to notify the calling subscriber that the recording apparatus is ready to receive his number. Dialled impulses are now received by relay 5, the armature 26 of which carries a stylus 29 for making a record of the number on the paper strip 30. After wheels 31, 32 have made a complete revolution, cam 35 strikes locking pawl 38, opening contacts 17, 18 to release relay 5 in case the calling subscriber has not hung up; and allowing armature 10 to fall back and stop the rotation of the gear-wheels and the paper feed rollers. In a modification, a sluggish relay is employed in the line circuit in series with a separate impulse-responding relay, and the apparatus for locking armature 10 is then unnecessary.