Patent GB-704441-A (GB)
Title: Automatic telephone systems provided with toll recording facilities
IPC: H04M15/04
Filed: 1952-05-08
Abstract: 704,441. Automatic exchange systems. AUTOMATIC ELECTRIC LABORATORIES, Inc. May 8, 1952 [June 15, 1951], No. 11675/52. Class 40 (4) A telephone system comprises automatic switching apparatus selectively operable by certain code digits or combinations of code digits for gaining access to appropriate trunks and one relay corresponding to each trunk for recapturing the related code digit or combination of code digits. Local calls.-When a call is initiated at T1, the line circuit 501 is controlled in known manner to cause distributer 503 to assign an idle finder-first selector link 504, 505 so that the finder finds the calling line. The first, second and third code digits RA6 lift the wipers of the first, second and third selectors 505-507 through 7, 2 and 6 steps respectively to give access to the local switch train 508-510. Operator and intercepted calls.-To call the operator at position 511, the subscriber dials O. Similarly if digits 1, 2, 4 or 6 or the combinations 71, 73, 75, 78, 79, 70 or 722, 724, 725, 728, 729, 720 are dialled, the calls are intercepted at 511...  Call from subscriber on exchange RA6 to subscriber on exchange WA2.-Connection to register translator. The first selector 505 responds to the digit 9 to seize an idle trunk 610 and energize line relay R620 in the local access circuit 600. R620 operates hold relay R630 which grounds conductor 613 to mark all the branches of the trunk busy at the various levels of the first, second and third selectors.  Ground on the fourth wire of the line circuit is extended over conductor 9MC to energize mark relay 9M which locks up and prevents energization of the other mark relays. An idle register translator 900 is normally associated with a local access circuit 600 through a finder 670, but if all the register translators are busy a chain circuit operates all-busy relay R1010 which prevents operation of the finders 670 and' grounds busy conductor 1013, which marks the trunk 610 and local access circuit 600 busy to the various selectors. When hold relay R630 operates as described above, it  energizes cut-through relay R650 which grounds  finder wiper 671 to mark the associated registertranslator busy. R650 also operates the appropriate gang relay R660 which energizes seize relay R1050 in the register translator and line relay R1150 in the trunk selector repeater 1100. Registration of called number.- The operated mark relay 9M grounds the first skip conductor in cable MX to operate set relay R935 and test relay R930, the latter operating rotary magnet RS4 to cause the register sequence switch RS to skip first office register 01 and establish connection with second office register 02. R930 restores and R935 connects impulsing wheel 937 to operate the rotary magnet 013 of the first office register intermittently until wiper O11 finds at the ninth contact the ground supplied by mark relay 9M, when transfer relay R940 operates. Vertical magnet OC10 follows magnet 013 to raise the wiper carriage of office composite switch 9 steps, so recapturing the first code digit. For the second digit 2 series relay R920 pulls up and rotary magnet 024 follows line relay R620 to register the digit in the second office register 02. R920 controls step relay R925 and magnet RS4 to drive the register sequence switch to third position. In a similar manner the other digits are registered in 03 and NI-4. Registration of calling number.-Operation of line relay R1150 in the trunk selector repeater 1100 energizes hold relay R1155, which grounds conductor 533 to operate detector 520, the finder 530 associated with the detector then finding the trunk selector repeater to energize detect relay R1140. R1140 operates gang relay R710 and also replaces ground on control conductor 613 of trunk 610 by booster battery 1122 to cause the detector to detect the directory number of the calling line and energize the appropriate relays of WXYZ relay marking groups M700, 0700, D700, U700 in the local access circuit 600. When detection is complete finish relay R530 pulls up to release R1140, and the operated relays in the WXYZ groups energize register relay R1135 slowly, whereby the detector is dismissed. Translation.-As previously described, the wiper carriage of office composite switch OC was lifted 9 steps in accordance with the value of the first code digit. Wiper 021 grounds the wiper OC2 in accordance with the second code digit 2, and the third digit is repeated by rotary magnet 034 to the rotary magnet OC11 to drive the wiper carriage an appropriate number of steps in the rotary direction to a contact jumpered to a contact in the vertical and rotary control contact banks of the office route switch OR. Registration of the third numerical digit operates springs N35, Fig. 10 to cause impulsing wheel 1034 to operate vertical magnet OR9 of the office route switch repeatedly until the vertical control wiper OR1 engages the contact 'connected through a resistance to the contact grounded by the office composite switch OC so that vertical test relay R970 pulls up. R970 locks up and causes rotary magnet OR10 to be energized repeatedly from impulsing wheel 1034 until rotary control wiper OR2 engages the grounded contact to energize rotary test relay R975. In the example, wiper OB4 engages a contact connected to the 4th marking conductor in the cable N and wipers OR5-OR8 engage contacts connected to the skip conductor SK so that the translation is a single routing digit 4. Sending.-When the third numerical digit is registered in N3, the register sequence switch RS moves to its seventh position where wiper RS2 applies ground to impulsing wheel 1035 which drives the digit send switch DS. In position 2 wiper DS1 operates shunt relay R1060 to operate the magnet SS4 of the send sequence switch SS. At each subsequent step of wiper DS1, R1060 interrupts the connection between impulsing conductors 912, 913, and each operation of contacts DS5 sends an impulse to line relay R1150 in the trunk selector repeater. In the example, after the sending of 4 impulses, wiper DS2 in sixth position makes connection over the fourth conductor of cable N to the wiper OR4, so that ground is applied over stop conductor SP to operate stop send relay R1070. R1070 shunts the impulsing circuit for line relay R1150 and releases SS4 to step the send sequence switch to position 2. R1070 also operates a self-interrupting circuit to send switch DS home, where R1060 and R1070 relapse. The routing digit 4 has thus been sent to line relay R1150, hold relay R1155 and series relay R1170 staying up during the train, while vertical magnet M1114 follows the line relay to raise the wiper carriage of switch 1110 four steps to select a group of trunks in the desired direction. At the first step springs 81118 operate to energize step relay R1175. At the end of the routing digit, R1150 holds to restore R1170 so that rotary magnet M1115 and step relay R1175 co-operate to step the carriage in a rotary direction until an idle trunk is found, when a circuit from ground over conductor 663 of trunk 610 is completed to energize switch relay R1180, which connects conductor 663 to wiper 1113 to seize the selected trunk. R1180 also energizes dial relay R1165 and releases hold relay R1155 slowly, the latter operating tabulator relay . R1145 and release magnet M1117. The trunk repeater 1100 has now finished operating as a selector in response to the routing digit. and is ready to act as a repeater. The trunk circuit 212 thus seized causes the seizure of a register translator in the called exchange. Repeating called number to called exchange.- When wiper SS3 engages the second contact, ground is connected over wiper OR5 to the skip conductor SK to advance the send sequence switch again, the switch being advanced stepby-step in a similar manner for the other wipers OR6-8 to sixth position where wiper SS3 grounds wiper 012 of the first office register 01, which is still registering the first code digit. Wiper SS3 also grounds conductor 915 to operate, pick-up relay R1190. Meanwhile, restoration of stop-send relay R1070 causes impulsing wheel 1035 to advance digit send switch DS to send the first code digit over impulsing conductors 912, 913 to line relay R1150, the train ending when wiper DS2 finds the contact grounded by wiper 012. Stop-send relay R1070 then re-operates to effect re-cycling of the register translator. Line relay R1150 repeats the digit to the register translator in the called exchange and also through series relay R820 and over wiper RSS1 to rotary magnet R13 in the local access circuit 600 so that the digit is stored in register R1, Fig. 8. At the end of the train, slow release of R820 causes advance of register sequence switch RS to second position. The other digits are transmitted in a similar manner to the register translator in the called exchange and to registers R2.R7. When send sequence switch SS reaches position 13, switch relay R640 operates to connect the calling line directly to line relay R1150 and dismiss the register translator 900. Connection to called line.-The code and numerical digits sent to the called exchange control the appropriate switches, signals to the calling subscriber being passed by windings 1131, 1132 and 1133, 1134 of repeater 1130. If the called line is busy, busy tone is returned. If the line is idle, when the called subscriber answers the current in the loop is reversed to energize answer relay R1160 to operate start relay R781 and hold relay R783 in the timer. When the called subscriber hangs up, R1160 falls back to stop the timer. When the subscriber hangs up to release the connection, removal of ground from control wiper 1113 restores switch relay R1180 which releases pick-up relay R1190 and operates release magnet M1117 and tabulator relay R1145. R1145 locks up and grounds conductor 613 to mark trunk 610 busy and hold switch relay R640 operated. The switch 1110 and magnet M1117 then restore. Metering-Tabu