749,171. Automatic exchange systems. AUTOMATIC ELECTRIC LABORATORIES, Inc. Sept. 7, 1953 [Sept. 11, 1952], No. 24701/53. Class 40 (4). Metering apparatus at a central exchange records calling and called numbers in connections from the central to a remote exchange and also in the reverse direction. General arrangement, Fig. 15. In a call from a subscriber at central exchange B to a subscriber at the remote exchange C, the line circuit 120, distributer 123 and finder 121 operate in known manner. The subscriber then dials the necessary digits, say 90-6-521. The first digit selects an idle ticketer 700 and the second digit causes a detector 1900 to detect the calling line and the calling party so as to register the directory number of the calling subscriber in the ticketer 700. The third digit 6 is repeated by the ticketer to a trunk selector 801 which seizes an idle trunk circuit extending to a ticket repeater 900 in the wanted remote exchange C. The remaining digits complete the connection to the called subscriber. When the called subscriber answers the ticketer 700 starts timing the call and at the end of conversation the ticketer is associated with a tabulator to record the metering information. In a call in the reverse direction the local connector 1319 returns dialling tone. The subscriber at the remote exchange C now dials digits, say 90-521-4-4574. The first digit 9 causes the local connector 1319 to seize an idle ticket repeater 900 and the digit 0 causes the ticket repeater 900 to seize a trunk circuit 810 in the central exchange B so as to seize an idle ticketer 700. The identity of the calling party on a party line is registered at this time in the ticket repeater 900. The subscriber then dials his own directory number 521 and these digits are registered in the repeater 900 and in the ticketer 700. A verifier 1301 is then associated with the repeater 900 and if the calling number is found correct the verifier permits the repeater 900 to transmit subsequent digits to the ticketer 700 to complete the call. The information stored in the ticketer 700 is then transferred to the tabulator 745. Local calls are not recorded. Detailed description. Party line signalling devices. The dialling devices are of known type, stations on a party line having cam springs 111a-115a, Fig. 1, for sending a fixed number of station identifying ground impulses between certain loop impulses (Figs. 16, 17, not shown). Call from central exchange B to remote exchange C. In response to the closing of the loop the line is extended in the manner described in Specification 368,716 to the first selector 122 which returns dialling tone. In the example the subscriber now dials 90-6- 253. The first digit operates the first selector to seize an idle ticketer 700 by energizing seize relay R650, which operates line cut-in relay R450 to extend the line conductors through the left-hand windings of repeating coil 490 and a loop including local line relay R430 and polarized party line relay R420, only the former operating at this time. R430 operates control relay R50 which busies the ticketer and operates slave relay R480 to energize control relay R610. R610 energizes the lower polarizing winding of answer relay R270 which does not operate yet. Local line relay R430 operates pulse control relay R485 at the first pulse of the next digit 0 so that the digit is repeated to magnet M663 of the 0 register 660. In the interdigital pause R485 falls back and, according to whether 0 has or has not been registered in register 660, operates R640 or R470. In the latter case R470 breaks the circuit to pulse control relay R485, to prevent its response to further digits, and returns busy tone to the calling line. On the other hand correct registration of digit 0 causes R640 to prepare a circuit for transmitting subsequent digits to wiper 503 of the receive sequence switch 501 and operates detector start relay R220 to cause detector 1900 to register the calling number in the code storage register 302 in known manner. In the case of calls from a party line, party line relay R420 and local line relay R430 operate in turn to ground and normal impulses one or more times to operate R310-R350 in turn according to the number of the station, this information being conveyed to the detector 1900 by grounding of the appropriate conductor PTY1-PTY5 or PTY0 if the calling subscriber is on an individual line. When this operation is complete R150 operates to dismiss the detector. If the detector fails to identify the calling number detector failure relay R140 operates to light an alarm lamp and lock the ticketer 700 until the exchange attendant momentarily operates key K145. Operation of R640 following the proper registration of the digit 0 restores line cut-in relay R450 to disconnect the loop from R420 and R430 and connect it to line relay R440, which energizes the line relay in trunk selector 801. Registration of called number in ticketer 700. The next digit dialled 6 identifies the called exchange and is repeated by line relay R440 to the trunk selector 801 and in parallel to the called office digit register 540. Operation and release of pulse control relay R485 operates and releases R590 to advance receive sequence switch 501. The subsequent digits 253 are repeated by R440 to the switching apparatus in exchange C and also to the thousands, hundreds and tens digit called number registers 550-570, the units digit register 580 not being used in this example. At the end of dialling, seize relay R650 remains operated to prevent false registration in register 580. Connection to the called line takes place in known manner through connector 1320. Timing conversation. When the called party answers current flow is reversed to operate answer relay R270 which energizes timer start relay R620. R620 operates self-interrupting magnet M707 to advance storage transfer switch 701 one step. R620 also applies time pulses to the conversation timer 635 which marks the duration of the conversation on contacts 7, 8, 9 accessible to wipers 702-705 of the storage transfer switch 701. At the end of conversation line relay R440 restores to reoperate R485 and release R410 which restores R485 slowly. R485 releases M505 so that receive sequence switch 501 advances to position 4. Release of R410 also restores control relay R250 slowly to operate release guard relay R230 which remains operated until all information is transferred from ticketer 700 to tabulator 745. R250 also releases the connection in a conventional manner. Connection and operation of tabulator. Release guard relay R230 operates allotter start relay R680. R680 causes tabulator allotter 744 to seize an idle tabulator 745 which finds the ticketer and operates cut-in relay R670 to restore R680. The tabulator and tabulator allotter are as described in Specification 692,999. Transfer is effected from the calling number storage registers 301, 302, called number storage registers 540-570 and conversation timer 635 through switch 701. As no registration has been made in the units called number register 580 in a call to exchange C, calling exchange relay R720 is operated under control of seize relay R650 to register a space instead of the fourth numerical digit of the called munber. Operation of R720 also causes the marking on the X23 and Y23 conductors to be transferred to record the calling exchange as B whereas if R720 were normal the marking would be on the Y23 and Z23 conductors to record the calling exchange as C. When transfer is complete the tabulator drives the switch 701 home, where wiper 706 restores control relay R610 and release guard relay R230 to drive all switches to home position and dismiss the common apparatus. Lamp L244 is lighted during the release cycle, unduly long illumination indicating a fault. Call from exchange C to exchange B. Closing the loop operates line circuit 1315, distributer 1317, line finder 1318 and local connector 1319 in known manner. In the example the subscriber then dials 90-253-4-4774, these numbers respectively giving access to the ticket repeater 900 and a trunk repeater 810 in the central exchange, indicating the calling number, the wanted exchange and the called number. The first digit 9 operates local line relay R970 in ticket repeater 900. R970 energizes hold relay R1030 which operates outgoing control relay R920 and control relay R190. R920 connects the conductors of toll line TL811 to the left-hand windings of repeating coil 925 so that the ticket repeater 900 may seize the trunk repeater 810 and an idle ticketer 700 in the central exchange and repeat certain dialled digits to the switching apparatus there. R970 repeats the digit 0 through contacts of pulse control relay R940.operated at the beginning of the digit to set the 0 register 915. At the end of the digit R940 falls back to energize R960 if 0 has been properly registered or R930 which energizes fault relay R985 if 0 has not been registered. In the latter case R985 operates failure relay R990 which supplies busy tone and shunts impulsing contacts 951 to prevent R950 repeating subsequently dialled impulses over the toll line TL811. During the dialling of 0 the party line station identifying register 1201 is operated in known manner. Dialling digits of calling number. Assuming that 0 has been correctly registered the three digits of the calling number are repeated by line relay R950 to the trunk repeater 810 in the central exchange and also to magnets M1171, M1181, M1191 to register the digits on switches 1170, 1180, 1190, the transfer from switch to switch being effected by the cooperation of step relay R1160 with transfer relays R1130, R1135, R1140, R1145, R1150, R1155, the last pair operating in series at the end of the third digit to operate the calling number register relay R1040 provided the last digit dialled corresponds to the number of the station registered by the party line station identity