GB482014A - Improvements relating to telephone systems - Google Patents

Abstract

482,014. Automatic exchange systems. SIEMENS BROS. & CO., Ltd., and VOSPER, W. T. Feb. 26, 1937, No. 5830. [Class 40 (iv)] In an outgoing repeater which sends break impulses over the outgoing loop, the latter is controlled by the impulse receiving relay A and by two auxiliary relays AA, AB at make contacts a1, aa3 in series and at a break contact ab4 in parallel with a1, the arrangement being such as to prevent the make and break periods being shorter than the permissible minimum. At each impulse, A, AA, AB fall back in succession and reoperate in the same order, so that the break period depends on, the release lag of AA, AB and the operating lag of AA and the make period depends on the operating lag of AB. Relay AB is made to operate more slowly than it releases by means of a winding normally shunted by a resistance YG, while the initial operating circuit includes a resistance YE which is cut out during impulsing. Upon seizure, the operation of A, AA, AB is followed by that of release relay B and switching relay HA, and dialling relay C pulls up at the first impulse of each train and holds by virtue of a short-circuited winding. Relay BB, which is connected up by C, energizes MD and is held between trains by the operation of I over the outgoing loop. The operation of polarized relay D and its auxiliary relay DD upon reply disconnects MD and places DA, DB under the control of S, Z pulse wires. During the period that these two relays are both energized, metering impulses are delivered to DC and are repeated over wire P. Relay I responds to busy flash, and its first relapse and reoperation connects up BR in place of BB whereupon the flash condition is repeated back by DD, the outgoing loop being maintained while A, AA are back by BR, which is held by DD.