Patent GB-222517-A (GB)
Title: Improvements in party line telephones
IPC: H04Q5/00
Filed: 1924-09-29
Abstract: 222,517. Hastings, E. F., (Executrix of Hastings, R. C. M.). Sept. 28, 1923, [Convention date]. Party-line systems and apparatus.-In a partyline system of the lock-out kind with step-by-step circuit-controlling apparatus at each substation controlled from the exchange, mechanism under the control of the receiver hook co-operates with the circuit-controlling device to place the substation in talking connection with the exchange. The invention is described as applied to a party-line system with ratchet-operated substation selectors controlled by impulses from a manual exchange, when the receiver is removed at a substation the exchange being signalled, and upon the operator inserting an answering plug in the calling-line jack, a preliminary impulse being automatically sent over the party-line to cut off therefrom all the substations except the calling one. The operator then ascertains the wanted number, inserts the calling plug in the corresponding party-line jack, and sends a series of impulses over the called line to step the selector at the wanted substation to ringing position. Provision is made for ring- ing a substation although the receiver thereat has been removed from its hook. Substation apparatus. The selector disc D, Figs. 1 and 2, comprises two members 12<1>, 13<1> of different diameters, clamped together on a spindle 4' so as to provide an annular shoulder which is pierced with inclined guideways 15<1>, 16<1>, Fig. 12, through which a pin N mounted on a pivoted lever A, is adapted to pass in moving from a position in which it rides on one side of the annular shoulder, to a position in which it rides on the other side. The support 40<1> on which the lever A is pivoted, carries three springs 15, 16, 183, the centre spring 16 being connected to the lever A. The selector disc D and the spindle, 4<1> are rotated by a ratchet-wheel 5<1> and pawl 10' actuated by a stepping magnet 60. Provision is made whereby in a certain arbitary position of the disc D, which position differs in each substation on a party-line, a pair of ringing contacts 167, 168, Figs. 4 and 30b, mounted on the support 40<1> beneath the springs 15, 16, are closed by a pin p on the disc D. The left-hand end of the spindle 4' is reduced and carries a sliding sleeve 19<1> adapted to be moved to the right, against the tension of a spring 20', by a pivoted lever 26<1>, which in turn is moved by a plunger 29<1> when the wall-set receiver is removed from its hook R'. Pins 21<1>, 21<11> pivoted to the sleeve 19<1>, pass through holes in the disc D, and when the sleeve 19<1> is moved to the right, respectively rock two levers 23', Fig. 4, which are mounted on the disc D and when rocked in this manner cause a shoe 24<1> to close the guide 15', and a shoe 25<1> to close a slot 18<1> in the periphery of the disc 13'. Thus when the receiver is removed, the shoe 24<1> moves the pin N from its normal position, as shown in Fig. 12, to the position shown in Fig. 15, this movement of the pin N turning the pivoted lever A and closing two spring contacts 15, 16, Fig. 1. The movement of a link 31<1> connected to the receiver hook R' also closes two contact springs 10, 11. A luminous visual signal 58<1>, Fig. 4, is mounted on the lever A and shows through an aperture in the casing when a substation is busy. The invention is also described as applied to a desk-set. In this modification, the selector disc D<1>, Figs. 19 and 21, is provided with peripheral notches 48<1>, Fig. 24, which are adapted to be closed, as shown in Fig. 27, when the receiver is removed, by two arms 50<1>, Fig. 21, on a disc 47<1> feathered on the selector shaft 4<111>. The disc 47<1> is adapted to be moved along the shaft 4<111> by the forked ends of a pivoted lever 45<1>, Fig. 19, which is turned by the end 43<1> of a pivoted rod, which extends through the tubular transmitter support, and is rocked when the receiver is removed. Ringing and talking contacts 167<1>, 168<1> are adapted to be closed both by the pin N' on a pivoted arm, and by arbitrarily-positioned pins 52<1> on the disc D<1>. The disc D<1> goes through two selective cycles in a complete revolution. Luminous visual signals 56<1> are mounted on arms 55<1> carried by the shaft 4<111>, and are visible through an aperture in the base of the instrument to give a visual indication when the station is busy. Arms 53' are also carried by the shaft 4<111> for stopping the selector in one of its normal positions on restoration. Wall set; calling the exchange operator. On a subscriber removing his receiver R, Fig. 30<b>, the switch-hook contacts 10, 11 are closed and the pin N, Figs. 1 and 2, on the pivoted lever A, is moved by the shoe 24<1> through the guide 15<1>, Fig. 12, in the selector disc, to its talking side, that is, from the position shown in Fig. 12 to that shown in Fig. 15. A projection on the lever A thereby closes contacts 15, 16, and a circuit is closed for a line relay 2, Fig. 30<a>, which lights a calling lamp 25 to signal the operator. Locking out other stations on calling partyline. The operator inserts her answering plug P, Fig. 30a, into the jack J and closes a circuit for the relays 31, 30, 38 over the sleeve contacts 35, 36. The cut-off relay 38 energizes and extinguishes the lamp 25. During the interval between the response of the quick-acting relay 33 and the slow-acting relay 31, a current impulse from the battery B<2> is sent over both the partyline conductors 18, 7 in parallel. At each substation on the party-line, the charge from a condenser 57, Fig. 30<b>, is drawn through a relay 55, which at contacts 62, 63 closes a series circuit for itself and the stepping magnet 60, and at contact 69 connects a magnet 71 in parallel. The selector discs at all the substations are thereby rotated a single step, this having no effect at the calling station since the pin N has been moved through the guide 15<1>, but at all other stations taking the pin N past the guide 15<1> beneath the projecting edge of the disc 13<1>, and by preventing the closure of contacts 15, 16 cutting these stations off from the party line. When the relay 31 pulls up, the calling'subscriber's talking circuit is completed, the talking current being supplied over the windings of a relay 75, which opens the circuit of the supervisory lamp 210. Selection of wanted substation. The operator throws her listening key L to place her head-set across the calling line, and enquires the wanted number. Having found this, she inserts the calling plug P<1>, Fig. 30, into the jack of the partyline on which the wanted subscriber is located. A circuit is thereby closed for relays 130, 133 and the called line cut-off relay, the relays 130, 133 causing a current impulse to be sent over the wanted party line to step round the selector discs of all the substations on it a single step, in the same manner as described with reference to the calling line. The operator now throws her dialling key 153 to connect up the impulse sender 156, and dials the number of the wanted party, thereby sending current impulses from the battery B<6> in parallel over the party-line conductors to step round the selector discs at all the substations on the party-line. The slow-release relay 232 is energized over contacts of the dialling key 153, and keeps ringing and talking circuits open during the sending of the selecting impulses. The contacts 167, 168, Fig. 30<b>, at the wanted substation are closed by the pin p, and the pin N is brought opposite the groove 18<1> and shoe 25<1>. On the operator releasing the dialling key 153 and throwing her ringing key 169, ringing current from the generator 170 is projected over the called line, and actuates the alarm 180 at the wanted substation. The operator restores the ringing key 169, and on the wanted party removing his receiver, the contacts 10, 11 are closed and the pin N is projected through the groove 18<1> to the talking side of the disc D by the shoe 18<1>, thereby closing the talking circuit springs 15, 16, and opening the ringing circuit at contacts 16, 183. The called line talking circuit is completed over the relay 193, Fig. 30, which opens the circuit of the supervisory lamp 201. Release. When the calling or called party hangs up, the relay 75 or 193 relapses, and closes the circuit of the supervisory lamp 210 or 201. The operator then throws her dialling keys and transmits impulses to restore all the selector discs to their normal position. At each station the slow-release relay 71 is energized in parallel with the stepping magnet 60 during these impulses, and projects an arm 35<1>, Fig. 1, into the path of a pin 36' on the shaft 4' to arrest the selector disc in its zero position. Ringing a subscriber who has not replaced his receiver. At the calling and called stations, the pin N follows the dotted line path shown in Fig. 15, passing through the slot 16<1> to the underside of the disc member 13'. In all other stations the pin N passes along the underside of the disc 13' to the normal position opposite the shoe 24<1>. If the calling or called party has omitted to replace his receiver, the pin N in restoring is brought behind the shoe 24<1> and the subscriber is prevented thereby from calling the exchange. The operator can, however, call him by dialling the appropriate number. This brings the pin N on to the shoe 25<1> and the ringing contacts 167, 168 are closed by the pin p. The subscriber then replaces his receiver, the pin N drops in front of the shoe 25' and the operator steps the disc D to normal. Operation of desk set. When a subscriber removes his receiver, the pin N<1> is projected by an arm 50<1> through the groove 48<1>. Fig. 27, and closes contacts 167<1>, 168', completing a circuit 7<a>, 12a, 11<a>, 10<a>, 168<1>, 167<1>, 18<a>, Fig. 31, for the operator's calling relay. On plugging in to answer, an impulse is sent as in the wall-set system to all the stations on the cal