Patent GB-694787-A (GB)
Title: Improvements in or relating to automatic telephone systems
IPC: H04M15/08
Filed: 1950-06-12
Abstract: 694,787. Automatic exchange systems. AUTOMATIC ELECTRIC LABORATORIES, Inc. June 12, 1950 [July 8, 1949], No. 14664/50. Class 40 (iv). In line identification apparatus adapted to be incorporated in a system of the character described in Specification 516,348, a line finder automatically finds a calling line and thereby operates a storage device to store the directory number of the calling line, the stored number then being transferred to a register. The directory number need not correspond to the number of the terminal of the calling line in the banks of the line finder. Operation of allotter and line fimder. An allotter 600, Fig. 6, preselects an idle line finder, say 500, Fig. 5, relay R650 interacting with rotary magnet RM615 to step wipers 730-7 until wiper 736 no longer finds earth. When a subscriber A, Fig. 4, lifts his receiver to initiate a call, his line relay R420 operates to mark the calling line in the banks of the line finders and to bring up an allotter start relay R605, followed by R630, R620, R720, R670, R640 and R520. Vertical magnet VM575 interacts with R650 to raise the wipers 591-8 of the line finder 500, operating the vertical off-normal contacts VON581-6. On reaching the level of the calling line, vertical wiper 597 encounters marking battery which operates relay R610 to stop the wipers and release R670, thereby energizing relays R660 and R510 so that R610 is shunted and falls back. Rotary magnet RM570 interacts with R650 to drive the line finder's two sets of rotary wipers 591-3 and 594-6, changing over the rotary off - normal contacts RON587 and RON588 to connect up test wiper 593. The operation of R510 also energizes a rotary magnet RM206 and a slow-operating relay R560 which then releases RM206 to advance by one step the wipers 291-8 of a switch 205, Fig. 2, individual to the line finder 500. Meanwhile the line finder wipers 591-6 continue to rotate until one of the two test wipers, 596 in this case, finds the marking battery on the calling line. Test relay R710 operates, stops the wipers, and brings up a relay R680. Switching relay R510, associated with wipers 594-6, remains operated while switching relay R520, corresponding to wipers 591-3, restores to normal and completes a stepping circuit for rotary magnet RM206 which drives wipers 291-8 until wiper 297 encounters battery potential, indicating an idle register-translator, Figs. 2 and 3. Test relay R550 energizes in series with rotary magnet RM206 whose further operation is prevented by the high resistance of R550. Registration of directory number of calling line. A register-translator seizure relay R220 operates and brings up, in a common registertranslator controller 100, Fig. 1, relays R160A, R180A, and R120 associated with the seized register-translator. The corresponding relays associated with the remaining register-translators are thereby disconnected to prevent the seizure of the register-translator controller 100 by another register-translator. Relays R250 and R310 now operate to initiate registration of the calling number. The ten thousands and thousands digits are indicated by the particular line finder 500 seized, and the corresponding register relay, R260 in this case, is energized over wiper 296. The hundreds, tens, and units digits are stored in marking relays in the register-translator controller 100 by means of suitable connections through cables 199A, 198, and 197 respectively. The hundreds digit is determined by which of the switching relays R510 and R520 is energized, the tens digit by cross-connections from the contacts of vertical wiper 598, and the units digit by a connection from the calling line circuit 400. The stored digits are transferred in code to the register-translator where corresponding combinations of register relays are operated. When at least one relay in each of the hundreds, tens, and units digits registers has been energized, relay R395 operates, followed by R540, R170A, R690, R530, and R410. R560 falls back and releases R550 which, together with the operation of R170A, initiates the release of the register-translator controller 100 and relays R250, R310. R690 initiates the release of the allotter 600, while R410 releases R605 and with R530 connects the calling line through the line finder 500 to the registertranslator. The caller now receives dial tone and proceeds to dial the wanted number. This is registered in the register-translator, which in general operates in the manner described in Specification 516,348. The registered information is transmitted to subsequent switching stages under the control of a sequence switch RS6X. When its wiper 300X reaches its last contact, a relay R210 is energized and releases R540 to switch the calling line through to subsequent switches and hence to the called line and also to release R220 which removes the holding earth from the operated register relays. These fall back, together with R160A, R395, R170A, and R210, so that the registertranslator is now released. The line circuit 400, the line finder 500, and subsequent switches are released in the normal way when the parties hang up at the end of the call. Specification 366,143 also is referred to.