Patent GB-192682-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1922-10-19
Abstract: 192,682. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Madsen, F. T.). Feb. 4, 1922, [Convention date]. Automatic exchange systems; metering systems.-In a zone metering system in which the charge for a call is determined by the distance between the originating and final exchanges, an impulse repeater E is associated with an outgoing trunk from the originating exchange, which picks out zone metering circuits 221-223, Fig. 4, connected to the metering switch S<6> according to the zone of the final exchange. When the called subscriber answers, the switch S<6> causes the operation of the meter by booster impulses over the incoming test conductor through one winding of a differential relay. A time switch CT causes the impulses to be repeated at definite intervals as long as conversation continues. The invention is described with reference to the system shown in Fig. 5, in which means are provided for preventing a subscriber making a call beyond the 4th zone. A call to the 3674th exchange in the 4th zone is extended through a selector and repeater E at the exchange O, a selector F and repeated E<1> at the 3rd exchange, &c., only the repeater E being effective for metering. The assessing apparatus, Fig. 4, is individual to the repeater with the exception of the timing devices T, CT and the tone machines TM, TM'. Repeater E. The outgoing trunk conductors are bridged through the lower winding of a polarized relay 104 and an impedance 105 through a repeating contact 110 of the line relay 101. During the passage of impulses, a slow relay 103 is energized, shunting the relay 104 and the impedance 105. Assessing apparatus, Fig. 4. Dialling of the second digit 6 connects intermittent earth to the wire 126, whereby the rotary magnet 166 operates the switch S<1> to the 6th position, earthing the second zone metering conductor 222, the first zone metering conductor 221 having been earthed at the off-normal contacts 179 in response to the first impulse. Upon release of slow relays 136, 135 which were energized during the passage of impulses, an impulse is sent to the stepping magnet 165 of the switch S, moving it to the second position, connecting up the rotary magnet 167 of the switch S<2>, which in response to the sending of the third digit 7 is moved to the 7th position, earthing the third zone metering conductor 223. The switch S is again operated, and the switch S<3> earths the fourth zone metering conductor 224 in response to the fourth digit 5. Operation of the switch S now connects up a cut-off switch S<5>, which is rotated by the next set of impulses, and if an attempt is made to obtain a connection to an exchange in the 5th zone, closes the circuit of a cut-off relay 106, Fig. 2, which releases the connection to the selector F. The switch S rotates ineffectively in response to further impulses. Metering. When the called subscriber replies, the reversal of current in the trunk energizes the polarized relay 104, Fig. 2, connecting up a relay 138 which locks and connects the impulse conductor 190 to the magnet 213 of the metering switch S<6>. The timing device T includes a pendulum 232 and a relay 233 which interact to energize a relay 231 twice per second, connecting battery to the conductor 190, and driving the switch S<6>. The metering relay 137 is thus energized over the zone metering conductors 221-224 in turn, sending four booster impulses to a differential relay at the selector, which becomes unbalanced and operates the meter four times. In the fifth position of the switch S<6>, the relay 137 is connected up in series with a high resistance relay 139, which alone operates and locks itself, cutting out the stepping magnet 213 and connecting up the release magnet 214 of the switch S<6>, which is restored to normal, and connecting the conductor 191 to the stepping magnet 169 of the switch S<4>. Metering duration of conversation. The magnet 234 of the cumulative time device CT is connected in parallel with the relay 231, and the ratchet 236 is thereby driven through one revolution in half a minute. Once in each revolution a pin 244 operates .a spring 237, energizing a relay 230, which earths the conductor 191, and drives the switch S<4> one step. When the switch S<4> reaches the eighth position, that is, after four minutes' conversation, the relay 139 is released, again connecting up the metering switch S<6> and the relay 137. Just before this occurs, however, the pin 244 operates a spring 238, closing the tone circuit, which was connected to the lower speaking conductor by the energization of a relay 187 when the switch S<4> reached the seventh position, to warn the calling subscriber that the meter is at out to be operated. The release of the relay 139 also connects up the release magnet 176 of the switch S<4>, restoring it to normal. Release. The relapse of the line relay 101 energizes relays 136, 135, and upon de-energization of the slow relay 102, the release magnets 171 - - 175 are energized in parallel, restoring the switches S, S<1>, S<2>, S<3>, S<5> to normal. The relay 138 also de-energizes, connecting up the release magnet 214 of the switch S<6>. Direct trunking to a 4th zone exchange. Where a connection is extended to an exchange, e.g. the 33rd, in the 4th zone by dialling only two digits, the second digit impulses operate the switch S' to the 3rd position, closing a circuit for a relay 141 which earths the second, third. and fourth zone metering conductors 222, 223, 224, connects the, second contact of the switch S to the cut-off switch S<5>, and connects the 7th contact of the switch S<5> to the cut-off relay 106, to prevent calling beyond the 4th zone. Metering takes place as before when the called subscriber replies.