Patent GB-610204-A (GB)
Title: Switching arrangement for time-zone metering in automatic telephone systems
IPC: H04M15/04
Filed: 1943-05-06
Abstract: 610,204. Automatic exchange metering systems. TELEFONAKTIEBOLAGET L. M. ERICSSON. May 6, 1943, No. 7204. Convention date, May 7, 1942. [Class 40 (iv)] In a time-zone metering system, calls within a certain distance are metered under the sole control of assessing apparatus responsive to dialled impulses at the originating exchange, whereas in the case of more distant calls the zone rate is assessed at a distant exchange and is signalled back to the assessing apparatus at the originating exchange. As shown in Fig. 5, a satellite subscriber Ab1 is given access to a junction FL with which is associated a metercontrolling set MZ which subsequently controls metering in accordance with its response to dialled digits in the case of nearby calls. In the case of more remote calls, however, the record in MZ is wiped out and the tariff is assessed by apparatus KLR associated with an outgoing junction at the main office H. Impulses representing the tariff are then signalled back to MZ which subsequently controls metering accordingly. Discriminating and meter controlling set MZ. When the set is seized, battery is connected to wire d. Dialled impulses are received over wire a and operate stepping magnet MLM of the reverse-drive discriminator switch ML and a sluggish relay ZR1 which remains operated until the end of the train and energizes ZR2. At the end of each digit, the switch moves by self-interruption to a new starting position. On contacts 22 and 23 it gives impulses to the magnet ZM of another reverse-drive switch Z, which thus moves to position 3, and on contact 25, after the second digit, it operates ZR4 which locks up: If the call is a local one, a circuit is made after the third digit over wipers of both switches to wire g. This causes disconnection of + battery from wire d and its connection to wire c and the consequent restoration of both switches to their normal positions. If the call is an outgoing one but is to be time-zone metered under local control, the number begins with 9 and Z is moved to position 6 in response to the first digit and, at the end of the third digit, ZR3 is operated and locks up and prevents further stepping of ML on the relapse of ZR2. A circuit is made over wipers of both switches from wire TI, TII or TIII which carry impulses at a rate depending on the selected tariff over relay TR to wire b. When the subscriber replies, TR receives these impulses. After a certain number it actuates contact K which energizes ZR1. This is followed by ZR2 and an impulse is given over wire a to which the meter is now connected. TR then drops back and the action is repeated. If the call is a long-distance one, its first digit is O and, as a result, Z is stopped to position 8 and ZR3 is energized at the end of the first digit over the bank E of this switch and locks up. Subsequent digits are without effect on this equipment, but operate the apparatus shown in Fig. 4 as described below. In due course, apparatus therein interacts with stepping magnet ZM to cause the stepping of Z to a position in which it selects an appropriate impulsing wire. Meter-controlling apparatus, Fig. 4. Impulses received by this circuit energize ZR5 and step switch KL. The relays ZR5 to ZR8 and selector R operate similarly to relays ZR1 ... ZR4 and selector Z in Fig. 2. When the call is established, a momentary + connection is made to wire g to step a third switch V off normal and energize ZU10 which puts + on wire a and steps V to its next position. The impulse on a is repeated by means not shown to wire i, Fig. 2. The junction circuit at the satellite then sends by means not shown an impulse forward to cause V to be stepped on and to send another impulse back. This interaction continued until V reaches a position marked by KL and R, whereupon a circuit is made in the register controller over wire f to cause KL, R to be released. To enable fewer positions to be provided on R than would otherwise be necessary, a relay ZR9 is provided to discriminate between groups of digits, e.g. 43 and 45, which cause R to be set to the same position.