GB277115A - Improvements in and relating to telephone systems - Google Patents

Abstract

277,115. Marks, E. C. R., (American Telechronometer Co.). June 10, 1926. Metering systems. - A substation meter is operated by periodic reversals in the line current produced by compressing alternately pairs R1 R2, and R3, R4, Fig. 1, of carbon pile rheostats connected as shown in Fig. 6. Metering begins when the cut-off relay 13 pulls up in response to the insertion of the answering plug. A clock controlled cam 117, Fig. 2, controls with the aid of relays 120<1>, 121, 110, 111 a pair of electromagnets 105, 106 which operate through links to admit compressed air to one of a pair of cylinders 73, 74 and release it from the other. These cylinders are arranged to compress the resistances R1 - - R4 in pairs. The magnet operated interrupts its own circuit and prepares that. of the other. The rate at which the current reversals take place is controlled by back-stroke drive distributors 151, 152 driven by impulses from the cam controlled springs 114, 115 and arranged normally to connect up the relays 120<1>, 121 at every step. During slack times however, an arm 187 which rotates once in 24 hours energizes a relay 185 which disconnects the relays 120<1>, 121 from alternate terminals. Testing and adjusting. Measuring instruments 61, 64 are connected as shown in Fig. 6 for indicating want of balance in the rheostats. A switch 216 is provided for connecting a voltmeter 215 to individual rheostats. The pressure in the cylinders 73, 74 is indicated by gauges and may be adjusted by valves 83, 84. The degree to which the individual rheostats are compressed is varied by moving the operating shoes 79 along the rods by which they are carried. Switches- 210, 212 short circuit the contacts 176, 177 respectively on relay 185. Metering at different rates in accordance with the zone of the calling party, and with the timeof day. As shown in Fig. 4 the same clock controlled contacts 275, 276 control separate pairs of relays 260, 260<1>, &c, corresponding to the relays 120<1>, 121 through distributors 280, 282 which are arranged to deliver impulses to the several pairs at different rates. The relay 262 is operated through a further distributor 290 which halves the rate when 'the wires 298, 299 are not bridged by a clock contact such as 187, Fig. 2.