Patent GB-211974-A (GB)
Abstract: 211,974. Relay Automatic Telephone Co., Ltd., and Johnson, B. B. Dec. 1, 1922. Automatic exchange systems; metering systems.-Apparatus for controlling the operation of a subscriber's meter a variable number of times according to the destination of the call, and associated with a. connecting circuit which may be employed for calls to any destination, is set in accordance with the wanted number to one of a number of positions and, in returning from this setting to normal, controls the transmission of a corresponding number of metering impulses. The invention is described with reference to a system in which connections are established by relays only, the meter-controlling apparatus comprising a set of counting relays CR &c. permanently associated with a connecting circuit ABF, one or more of these relays being selected and operated by the usual temporarily-employed impulse-responder (not shown). Upon the release of a connection by the calling subscriber hanging up, the counting relays CR &c. pass through a cycle from their set position to their normal position, during which a number of booster impulses are sent out over the circuit 3 to operate the subscriber's meter SM. The arrangement is such that the release of the connection is dependent upon the last operation of the meter, whilst if the calling subscriber should again remove his receiver during metering, the operation of the meter is not interfered with and no other call can be initiated until the meter has been completely operated. The counting relays CR &c. are so arranged that to operate the meter 1, 2, 3 or 4 times, relay CR1-2-3-4 and one of the relays CR1-6 - - CR4-9 are operated, whilst to operate the meter 5, 6 - - 9 times one only of the relays CR5, CR1.6 - - CR4-9 respectively, is operated. If a call is made to a line for which no charge is to be made, no counting relay is operated. By way of example, a more detailed description will now be given of the operations of the system when it is desired that the meter shall be operated once or five times. Meter operated once. When the impulse responder has been fully set, a battery connection to conductors R1-6, R1-2-3-4, and the operation of relay OTM which takes place at the same time complete energizing circuits for relays CR1-6, CR1-2-3-4, which lock up respectively in circuits 7<e>, 7 to ground c over contacts of relay GX which is energized as long as the calling subscriber's receiver is removed. When the called subscriber replies, relay S<2>, operating in known manner, completes circuit 4 for relay ME which locks up over circuit 4<1> including front contacts of relay R1-6. At this time, meter SM is included in the holding circuit 3 but does not operate on account of resistance HR. Relay ME completes circuit 8 for relay CR5 which locks up over circuit 9<a> and transfers the locking circuit of relay CR1-6 to circuit 9 so that both relays CR5 and CR1-6 are locked to ground a dependent upon differential relav R which is not yet energized. When the calling subscriber hangs up, the release of relays G, GX, shortcircuits resistance HR so that meter SM operates once and, in doing so, short-circuits its right-hand winding, so unbalancing the circuit that relay R energizes and breaks the locking circuits of relays CR1-6, CR5 which de-energize. Relay ME is also unlocked and breaks the circuit of relay CR1-2-3-4, so that the relay set is restored to normal, whilst the relapse of relay ME breaks the connection to the connecting circuit ABF. Meter operated five times. In this case relay CR5 is operated over lead R5 and locks up over circuit 7<a>. When the called subscriber replies, the operation of relav ME completes circuits 10, 11 for relays OR, CR1-2-3-4, respectively, which lock up in circuits 15, 17, the latter relay transferring the locking circuit of relay CR5 from ground c to ground a dependent upon relay R. Relay CR4-9 is also operated in circuit 12 and locked over circuit 7<b>. When the calling subscriber hangs up, the release of relay GX causes the operation of the meter once as before, whilst the subsequent operation of relay R re-energizes relay GX to re-insert resistance HR, and unlocks relays CR, CR5. The release of relay R, due to the de-energization of the meter SM, causes relay CE3-8 to energize and lock up over circuit 7<c>, at the same time transferring the locking circuit of relay CR4-9 to circuit 9<c>. The release of relay R also causes relay GX to release and shortcircuit resistance HR to operate the meter a second time. Relays R, GX thus continue to control one another's circuits, a metering impulse being transmitted each time relay GX de-energizes. After the second metering impulse, relay CR4-9 is de-energized and relay CR2-7 energized; after the third impulse, relay CR3-8 is de-energized and relay CR1-6 energized; after the fourth impulse, relay CR2-7 is de-energized and relay CR5 energized. After the fifth impulse, relays CR1-6, CR5, both of which were locked to ground a, are deenergized so that relay ME also deenergizes and releases the connection, the counting relay group being completely restored to normal by the release of relay CR1-2-3-4. The circuits of relays which are normally operated when a subscriber removes his receiver to initiate a call are disconnected at contacts of relay ME during the metering operations so that, should the calling subscriber again remove) his receiver before metering is completed, he is prevented from effectively initiating another call or from interfering with the operation of the meter.