Patent GB-226587-A (GB)
Title: Improvements in electric selecting apparatus suitable for use in telephony
IPC: H04Q3/00
Filed: 1923-09-11
Abstract: 226,587. Relay Automatic Telephone Co., Ltd., and Ward, F. M. Sept. 11, 1923. Automatic exchange systems; selectors.-Relates to the construction of and circuit arrangements for numerical selecting apparatus employing " bar-relays," i.e. relays the armatures of which control ten sets of contacts one of which is selected for operation. Figs. 1 and 2 show an impulse recorder in which thousands, hundreds, and tens bar-relays BR1, BR2, BR3 operate contacts selected by a bar-relay BR controlled by an impulse-responding step-by-step switch SS, and the contacts of the bar-relay BR then serve to mark the units digit. Fig. 4 shows a connector having bar-relays BRL1-10 controlling horizontal rows of contacts. An impulse - responding step-bystep switch LS is rotated to select a column of contacts, and the bar-relay to be operated is selected by an auxiliary bar-relay BRC controlled by a second step - by - step switch RS. Specifications 221,881 and 225,932 are referred to. Impulse - recorder, Figs. 1 and 2. The calling subscriber is connected to a feed-relay group, which connects battery to wires A, B, H, Fig. 3, so that relay LI energizes in circuit 4 and locks in circuit 4a over the A and B wires. Relay RC1 corresponding to the first idle recorder energizes in circuit 5 in series with relay P, Fig. 1. and open-circuits relays RC2, RC3. Relay P connects battery to the recorder, energizing relays RSR1, RSR2, and connecting up stepping magnet SM, Fig. 2, in circuit 6 over a contact of relay BY. Assuming the dialled number to be 7856, at the first removal of battery from the A and B wires, relay FI falls back and connects the A and B wires through to the magnet SM at the recorder. Relay BY energizes in circuit 8 in series with relay P, breaking circuit 5 to mark the recorder busy, and breaking circuit 6 so that magnet SM advances the switch SS one step. Off-normal contacts ON are operated, and relay DC2 energizes in circuit 11 and connects up sluggish relay DC1 in parallel with magnet. SM. The switch SS selects the contacts of bar-relay BR to be operated by means of a spacing-member on its shaft. At the end of the first train of impulses, relay DC1 energizes and operates bar-relay BR in circuit 12. Contacts X, 8C are thus closed, and circuit 17 is completed through auxiliary relays STH, 8H, 8T and circuit 13 through controlling relays THP, HP, TP. Relay THP energizes, cuts out relays HP, TP and locks, so that the thousands bar-relay BR1 energizes in circuit 14 and closes contacts R1, R2, 8CM. Contacts R2 complete holding circuit 16 for bar relay BR1, contacts R1 complete circuit 15 for release magnet RM of the switch SS, and contacts 8CM prepare the thousands marking circuit. Bar-relay BR is released, and the switch SS returns to normal, relays THP, 8TH, 8H, 8T, DC2, DC1 being released. The second digit 7 is received in the same way, relay HP now energizing since con. tacts R2 are operated, and the hundreds bar-relay BR2 closes contacts R1<a>, R2a, 7HM. Similarly, the third digit 5 causes the tens bar-relay BR3 to operate contacts R1<b>, R2b, 5TM. When bar-relay BR energizes in response to the last digit 6, contacts X, 6C are closed, and the former complete circuit 13<a> for relays UMP. UP. Relay UMP closes the units marking circuit UMW over contacts 6C, and relay UP completes circuit 20 for relay MC, Fig. 1, which locks, closes a metering circuit 22, completes marking circuit 24 for the thousands and hundreds digits, and connects up relay MCX in circuit 21 to mark the tens digit and connect battery to the units marking circuit UMW. When the connection is completed, relay RCO operates, and relays RC1, P, BY relapse and release the recorder. If the wanted line is represented by a single digit, e.g. 2, contacts 2CM closed by the thousands bar-relay BR1 complete circuit 28 for relay MX2, which causes relays MC, MCX to energize in circuits 30, 31, so that marking circuit 29 is closed. Connector, Fig. 4. Line relay A and release relay G energize and close the impulse circuit through stepping magnet IM and relay E. The switch LS is thus rotated and a column of contacts is selected by means of spacing members L1 - - 10. Sluggish relay E falls back at the end of the impulse train and connects up change-over relay IC over off-normal contacts LX, transferring the impulse circuit to stepping magnet IR. The switch RS thus rotates spacing member RM to select contacts of bar-relay BRC. When relay E falls back, bar-relay BRC energizes over offnormal contacts RX and closes the selected contacts, so that the corresponding one of the barrelays BRL1 - - 10 energizes and closes contacts LC selected by the switch LS. Upon release, relay G falls back, and relay IC relapses and connects up release magnet RMC, and the operated bar-relay is disconnected and releases the spacing members.