Patent GB-773558-A (GB)
Title: Monitoring arrangements for telecommunication switching systems
IPC: H04M3/08
Filed: 1954-12-30
Abstract: 773,558. Automata exchange systems. VIGREN, S. D., and CLAESSON, P. H. E. Dec. 30, 1954 [Dec. 30, 1953; Aug. 9, 1954], No. 37684/54. Class 40 (4). An automatic exchange is provided with an automatic call supervisory device. The device is connected either by an allotter or at random to calls as they are originated and registers details such as digits received by the register, digits transmitted by the register, and types supervisory signals reverted. In the case of certain supervisory signals which might possibly indicate trouble, e.g. N.U. tone, all trunks busy tone, &c., the registered signals are permanently recorded and automatic tracing of the connection is initiated the route taken by the connection also being recorded. General layout, Fig. 1. Registers RE involved in setting up a connection, have their incoming and outgoing wires A1, B1, A2, B2 connectible over a switch V1 to devices J1 ... J4 which register information concerning the call being set up and determine whether a central recording device Rs shall be called in because e.g. abnormal conditions are observed. Such conditions may be (a) failure to complete connection within a predetermined time; (b) undue noisiness of the circuit; (e) busy tone received; (d) all trunks busy tone received; (e) N.V. tone received; (f) register indicates that the number dialled is singled out for special observation; (g) a very brief conversation such as might be due to the making of a wrong connection; (h) called party answers. Devices for indicating conditions (b), (c), (d), (e) and (g) are described Figs. 3(a) ... 3(e) (not shown). Condition (a) may be noted with the aid of a timing device set in operation on connection of register and restored say when tone signal e.g. ringing or busy tone is received. The recorder, having recorded the information registered on devices J1 ... J4, may then set in operation a connection tracing device N2 of the type described in Specification 772,735 from which it receives further information concerning the connection. Provision may also be made for recording speech &c. present on the line. In the subsequent description the numeral in brackets after a relay designation indicates the Figure in which it is to be found. In the drawings reference numerals for leads are followed by a hyphen and the number of the Figure in which the lead continuation is to be found. Connection of register to registration devices J1 ... J4. Register connecting relays R1, R3, R5, Fig. 2, are given a cyclically varying order of priority (in the case of simultaneous calls) by relays R2, R4, R6 one of which is normally operated, say R6. When a register is taken into use it operates a contact RE1 which brings up R5 and R9 the latter bringing up R8 which opens the operating circuit for R1 and R3. Relay R8 brings up R7. When the register is released RE1 is opened and R9, R5 and R8 release thereby bringing up R4 instead of R6 so that relay R3 receives priority in the event of simultaneous calls next time. The talking wires A1, B1, A2, B2 incoming and outgoing from the register are now connected over wires a1, b1, a2, b2 to the registering devices J1 ... J4. Speech recording device, Fig. 11. This is started by the operation of magnet R2 from control circuit, Fig. 5, but this magnet may be held from a source indicated by + inside a circle obtained from Figs. 6 or 9 as described later. The speech received on wires a2, b2 is amplified and passed to the recording head R1. A switch V3 is provided driven by a motor having three field windings operated by contacts T 1, 2, 3 operated in accordance with the movement of the recording medium. A second switch V4 is stepped over its forward stepping magnet I once per revolution of V3. The positions of these switches thus indicate the position of the recording on the medium. Further switches (not shown) may be provided indicating the identity of the recording medium (e.g. the number of the disc). Restoration is effected by release of R2 which causes the motor to run backwards. Contacts T 1, 2, 3 then restore V3. Relay R3 also comes up to connect up the backward slipping magnet II to restore V4. If the record is to be maintained permanently R6 is operated to inhibit the return movement by means not shown. Registering incoming digits, Figs. 6, 7. These are registered on successive bars of a crossbar switch. Relay R1 operates to the incoming line loop and is followed by R2. Dialling relay R3 comes up on the first impulse followed by R6. Impulses are then fed over contacts of R8 (which operates and releases on alternate impulses) to step a digit counting chain of which only four select magnets STM1 ... 4 are shown. At the end of the impulse train R3 releases causing the discharge of capacitor C1 to operate R4 momentarily to bring up hold magnet BRM1 which locks. When R4 releases R6 falls back to release the select magnet. Subsequent impulse trains are similarly recorded, R5 operating and releasing at the end of alternate trains to cause the successive energization of the appropriate hold magnets. Registering outgoing digits and reverted signals, Figs. 8, 9, 10. The outgoing digits are registered on a cross-bar switch using relays R1 ... R8, select magnets STM and hold magnets BRM just as in the case of incoming digits. Reverted signals consisting of current reversals (e.g. for the initiation of the sending of a further digit, or as a called party answer signal) operate polarized relay R22. Relays R11 ... R16 are thereupon operated, R12 bringing up R4 to operate the next holding magnet. R13 then releases R4. When the impulse terminates R22 and R11 release to operate STM1 whereupon R4 again operates to bring up the next holding magnet and register the reversal. R15, R16, R14 and R13 then release. On an abnormally brief current reversal R11 is locked up by R15 and R4 until the holding magnet is operated. The operation of R16 prevents interference by a second current reversal before the first is recorded. In the case of a long duration current reversal (e.g. called party answer signal) the slow release relay R13 releases whilst R11 is still up thereby causing STM2 to operate. R4 then operates to bring up the next hold magnet to register the reversal as previously described. When the polarity subsequently restores to normal release of R11 brings up R12 which operates R4 to bring up the next holding magnet. Relay R12 releases R14 which releases R12 again and R4 follows to bring up STM3. R4 reoperates to bring up another hold magnet whereupon R15, R4 and STM3 release. Forced release. This is initiated by unbalance on the a1, b1 wires, Fig. 6, to bring up R9(6) followed by R17(8). The latter is followed by R18, R19 and R4 which operates a further hold magnet. R20 then operates to release R18 and R4 whereupon STM5 comes up and R4 reoperates to bring up a further hold magnet whereupon R19, R4 and STM5 release. If ringing or busy tone has been received at this stage however R21 will have been operated from the detectors of this tone, Fig. 3c (not shown), and STM4 will operate instead of STM5. If forced release occurs during the reception of a current reversal R17 locks up and R18 is prevented from operating until R3, R11 and R15 are released. Recording general information concerning call. The detectors for N.U. tone all trunks busy tone and other signals which indicate that recording might be desirable, apply positive potential to associated leads 22 ... 26, Fig. 5, to bring up corresponding relays R1 ... R6. When one of these operates R7 and R8 follow, the latter putting a holding coil R9 across the incoming line loop a1, b1. Relay R8 brings up relay R5 (13) over the wiper of switch V1b in position 1; and also R3 (13) to connect up stepping circuits for the digit wheels S1 ... S20. Relay R5 brings up R10 followed by R11 which energizes the magnet of the reverse drive switch V1b. Relay R10 causes relays R10 ... 12 (5) to interact to produce stepping pulses for digit wheel S1 (13) and switch V1a. These step until wiper 1 of V1a (5) finds an operated relay in R1 ... 6 (5) whereupon R12 (5) is held to interrupt the stepping. The operated relay R1 ... 6 (5) is shunted down by potential over wiper V1a so interrupting the stepping circuit for the digit wheel S1. Relay R12 then reoperates and the stepping continues. Digit wheel S2 is also stepped by the impulses until wiper 6 of V1a (2) encounters an operated relay out of R1, R3, R5 (2) (indicating the identity of the register). The stepping is then halted temporarily as previously described and R10 (2) comes up to interrupt the stepping circuit for digit wheel S2. Digit wheels S3 and S4 are used for recording the tracks of the disc used for speech recording, the wheels being stepped over circuits made by contacts of relays R4, R5 (11) which relays operate to interrupt the stepping when wipers 2 and 3 of V1a encounter contacts marked over banks of switches V3 and V4. Digit wheels S5, S6 are used for recording the identity of the disc (circuits not shown). Digit wheels S7 ... 13 may be used for indicating the time of the call. When all these wheels have been set R10 releases followed by R11 during whose release time a magnet R2 is operated to cause the digit wheels to print the digits to which they have been set. R1 also comes up to home the digit wheels. Release of R11 steps switch V1b and when R1 releases R6 comes up over the wiper of V1b. Recording digits received by and transmitted from register. Relay R6 (13) brings up R10 over contacts of the hold magnets BRM (7), R10 brings up R11 and also starts the impulsing relays R10 ... 12 (5). With R6 now operated switch V1c (7) and the digit wheels S1 ... S20 are stepped. When a wiper (say the lower one) of V1c reaches a closed contact of the cross-bar switch impulsing is temporarily stopped, the corresponding hold magnet (BRM1) is shunted down to interrupt the stepping circuit of the corresponding digit wheel (S1).