Patent GB-439339-A (GB)
Title: Improvements in telephone systems and pay stations for use therein
IPC: H04M17/02
Filed: 1935-02-21
Abstract: 439,339. Automatic exchange systems. TELEPHON - APPARAT - FABRIK E. ZWIETUSCH & CO., GES., 6, Salzufer, Charlottenburg, Berlin. Feb. 21, 1935, No. 5624. Convention date, July 31, 1934. [Class 40 (iv)] [See also Group XVIII] The line from a paystation to the exchange terminates at each end in change-over contacts which in one position connect coin signalling devices to fee-recording switches at the exchange and in the other position connect the dial and telephone set to the exchange equipment for establishing the connection. The change over occurs when the dial is first moved off normal (with the receiver removed) in outgoing calls and when the receiver is removed in response to an incoming call, the difference in operation being due to a normally operated pay-station magnet (PM) released when an incoming call is connected to the line. The coin signals comprise impulses over the a and b wires for different coin values and these are recorded on exchange switches individual to the calling line. The number and value of the coins are converted into units and totalled on a switch available in common to a number of pay-station lines. Different night tariffs are provided for. One or two dialled digits are recorded on a further common switch which also discriminates between kinds of call, and the connection is released if the fee paid is incorrect. The system described uses digits 2 to 9 as first digits for local calls, 02-00 for short distance calls and 1 or 01 for free calls, e.g. to operators. In the case of short-distance calls, the number of units is also metered and for this purpose the record of the totalling switch is transferred to the discriminator (after release), and thence to one of the individual fee recording switches in order to avoid holding the common switches until the called party replies. Mechanical control, Fig. 1, of pay-station circuits. Removal of the receiver allows the descent of bar 4 which turns lever 6 counterclockwise about pivot 10. Lever 11 controlling the change-over contacts vk and connected to lever 6 by spring 14, tends to move clockwise to operate the contacts but is normally restrained by a hook 27 on lever 17 pivoted at 28. The restraint may be removed by a cam 19 on the dial shaft (for outgoing calls), or by the release on incoming calls of normally operated magnet PM the spring restored armature of which turns lever 17 clockwise against the spring 21. Coin control, collection and refund, constructional arrangements for. Channels 33, 41, 42, Fig. 2, are provided for three different coins. A coin of unit value inserted in channel 33 is thrown against gong 32 by projection 34 and falls on counterweighted lever 36 whereby cam 39 closes springs gk10 to transmit an impulse. The lever 36 swings clear of the coin which falls into shoot 53. A coin of 10-unit value in channel 41 strikes gong 31 twice (once at the beginning and once at the end of the channel), and moves lever 47 to such an extent that cam 52 operates impulse springs gk50 twice (once on the downward and once on the upward movement of the lever). A coin of 5-unit value in channel 42 however rings the gong once at the lower end of the channel and operates springs gk50 once only since cam 52 is not moved sufficiently for pin 13 to run past the cam projection 74. The coins fall on a tilting platform 55 controlled by a bar 60 and a pair of levers 77, 78. The coin collect magnet KM moves bar 60 to the left tilting the platform to the right so that the coin runs down shoot 85 into box 71. Magnet SM which is also energized prevents any possibility of refund during coin collection. For the refund operation, the platform is tilted in the opposite direction by movement of the bar 60 to the right, so that the coin passes into the refund shoot 72. Refund occurs only when magnet SM has been energized alone and when the receiver has been replaced. The replacement of the receiver lifts bar 4, but bar 87, which tends to follow it, is retained by detent 91. When the connection is released, SM de-energizes, the bar 87 released by detent 91 moves up, and lever 96 moves bar 60 to the left. The coin impulses and collect magnet are used only for local and short-distance calls. For long distance calls, the gongs and an auxiliary microphone signal the operator and collection is effected by pressing button 102 which moves bar 60 in the " collect " direction and strikes gong 106 to inform the operator. Circuit arrangements ; short distance calls. The coin-controlled impulse transmitting circuit including coin-controlled contacts gk10, gk50 is separate from the usual sub-station circuit and is normally connected to the exchange line at contacts vk, relay PM at the sub-station and G10, G50 at the exchange being normally operated from a ground at the pay-station, H remaining inert. Each single unit coin transmits an impulse from gk10 over the a wire to release G10. each 5-unit coin transmits an impulse from GK50 over the b wire to release G50 whereas a 10- unit coin similarly transmits two impulses over the b wire. These impulses are respectively repeated to magnets M10, M50 of switches W10, W50 which are 34 point switches and start from contacts 24 and 29 respectively so that the maximum fee is 9 single unit coins and four or two 5-unit or 10-unit coins respectively (M10, M50 each receive an additional impulse as will be seen later). When the receiver is removed, the short-circuit on PM(i) permits H at the exchange to pull up. B energizes and makes a driving circuit for line switch VW which is opened by test relay T, a temporary loop to the group selector being provided over a contact of B. Relay An in the common control circuit is also operated and starts switch AS in search of the calling line, relays P and PR pulling up when this is found. An falls back. Dialling is now commenced and the change over of springs vk at the sub-station switches over to the telephone set so that relays G10, G50, H fall back and magnets M10, M50 are energized and take a step their circuits being opened by slowly operating relay E energized by D on the relapse of G10, G50. The calling loop is now extended to relay A in a repeater at the line switch the temporary outgoing loop being replaced by a contact of A, relay B having been released. The impulses are repeated forward to set the switch train in the usual manner. The impulses are also repeated over slow releasing relay V and wiper IAS to VR and MW1 which steps W1 to a position corresponding to the sum of the first two digits. When wiper IIIWI goes off normal transfer of the coin record from W10, W50 to switch S commences, the transfer from W50 occurring first. Relay X pulls up over IIIWI in series with M50 which remains inert, and slow releasing relay WR pulls up to energize magnet MS which interacts with X to step S over 5 contacts whereupon a low resistance circuit is made over IIIS, IIIAS, W50 for magnet M50 which takes a step. Switch S continues taking 5 steps to every step of M50 until W50 steps off the 34th position whereupon X falls back, WR releases and U pulls up so that switch S takes further steps synchronously with W10 until wiper W10 steps off its 34th contact. Switch S has therefore taken a number of steps complementary to the number of single unit coins plus five times the complementary of the number 5 unit coins. If the fee recorded by wiper IS is correct for the sum of the digits recorded on IW1, cross connections between the banks of these wipers operate Y(i) and C(i). Relay C makes a homing circuit for MW1 over RV and holds over C(ii) until WI is normal. Relay Y(ii) holds over the off-normal arc VS, F(i) pulls up over VAS and holds over F(ii), and X re-operates and interacts to step MS home, MW1 being stepped synchronously so that the complementary record of S is transferred to W1, relays WR, TR being operated during this procedure. When S reaches normal, KR(ii) and Z(ii) pull up over VS, and C(ii) re-operates so that relays P, PR fall back and as Y is also released, N pulls up over IV AS in series with magnet M50 which remains inert until N operates magnet MW1 which shunts N to operate M50. Switches W1 and M50 are thus stepped synchronously to transfer the record of W1 to M50, the controlling circuit over VW1 being opened when W1 reaches normal. The control circuit is now free for use in another call and M50 records the actual number of units of the fee paid. Metering, coin collecting, and release.- When the called party replies, M(i) operates over IIIVW in response to potential applied in known manner to the b-wire, locks over M(ii), releases F and energizes K(i) over W50 whereupon M50 and K interact to step W50 to normal, K repeating impulses to the meter FZ. When the calling party replaces his receiver, SM, Fig. 3a, operates over switchhook contacts and holds in series with A(ii) which however does not remain operated in this circuit. The connection is therefore released and a booster impulse over the third wire operates ZR(i) which holds over ZR(ii) since V(i) has been operated by the release of A. Collecting potential is applied over relay P to operate KM during the release period of V the circuit of which is opened by P. When the line switch is released, the relapse of T operates AB which holds over contacts of G10, G50 and makes circuits over IIW10 for HR and over IIIW50 for K(i) and these relays interact with magnets M10, M50 to step the fee switches to their normal starting positions on contacts 24, 29 respectively. Relay D holds SM until this is done. When contacts vk at the sub-station have changed over, G10, G50 resume the normally operated condition, AB falls back and the line switch circuits are normal. Night tariff. Key Tu is thrown and shortcircuits G50(ii) to permit operation of a visual signal SZ at the sub-station. Another key contact substitutes wiper IIS, Fig. 3c for IS so as to change the cross connections between the switches recording the