Patent GB-191215057-A (GB)
Title: Improvements in Telephone Systems.
Inventor: CLAUSEN HENRY PETER
IPC: H04M3/523
Filed: 1912-06-27
Granted: 1913-06-27
Abstract: 15,057. Clausen, H. P. March 11, [Convention date]. Semi-automatic exchange systems; metering systems.-Subscribers' lines that originate a large number of calls are connected at the exchange to switches of preliminary-selector type which distribute the calls among idle operators. The other lines are connected to twoconductor multiple jacks at the exchange in the usual way, and the trunks from an operator's position may be made busy when there is any ordinary or distributed call waiting in the operator's group. An intermediate distributing-board is provided on which a subscriber's line may be connected to a distributing-switch or to the leads of multiple jacks. The figures show subscribers 1 and 2 connected at the intermediate distributing frame over contacts 24, 25, 26, and 35, 36, 37, to distributing-switches 44, and subscriber 3 connected over contacts 24, 25, 26, and 27, 28, 29 to multiple jacks 23. The operator's cord circuit is the same for connecting with either kind of subscriber. When a call is made by subscriber 3 the line relay 14 is energized in the usual way and a circuit is completed from the battery lead 15 over the contacts 22, 23 to the line-lamp 32 and the pilot relay 33. The contact 131 of the relay 33 brings into circuit the pilot lamp 132 and the meter magnet 133, which thus registers one call. The contact 129 of the relay 33 completes a circuit for the magnet 101, which by closing its contacts 87, 88 connects to earth the distributing trunks 98 of this position, thus rendering the position busy. When the operator inserts a plug in the jack of the calling line, the cut-off relay 13 is energized from the battery 16 over the sleeve contact 31. The line-relay 14 and the relay 33 being thus de-energized, the busy condition is removed from this position. After enquiry, the operator tests the line of the desired subscriber, as 3<1>, by touching the sleeve 23<1> with the plug tip 141. If the line is busy, current will flow from the sleeve over the contacts 168 of the listening key to the instruments and to earth at 173, the click of the receiver being the busy signal. In the case of an idle line, the plug is inserted and the ringing key depressed to connect the battery line over the resistance 178 and the ringing generator 177. When the ringing key is released, a circuit is made over the supervisory relay 159 and the cut-off relay 13<1>, thus displaying the signal 166 until the subsscriber 3<1> answers, whereupon the supervisory relay 158 is also brought into circuit and the circuit of the signal 166 is broken. When subscriber 2 makes a call, his line relay 14 is energized as usual, and a circuit is completed from battery lead 15, over contacts 22, 23, motor relay 48, and trouble relay 62. The contact 53 of the relay 48 connects the secondary 57 of the busy signal apparatus to the sleeves of the jacks of this line. The contact 79 of magnet 48 brings the motor magnet 81 into a circuit extending from the interrupter 83 over the magnet 81, the contact 79, contact 71, switch segment 76, brush 84, contact 92, and lead 98. If the position to which the trunk 98 leads is busy, the contact 99, 87 is closed by the magnet 101 and the above circuit is completed to earth. The magnet 81 therefore rotates the switch until an idle trunk 98 is found, whereupon a circuit is made from battery lead 15 over relay 106, contact 104 of the jack 95, contacts 100, 99, lead 98, brush 84, segment 76, coil 72 of cut-in relay 40, and contacts 73, 52 to earth. The relay 106 completes a locking circuit for itself and connects the line 98 to earth, thus preventing another switch from selecting the jack 95. The contact 113 of relay 106 makes a circuit over the line-lamp 114 and the pilot relay 116, which brings into circuit the pilot lamp 119 and the call counter 120. The contact 118 of the relay 116 also brings into circuit the relay 101, thus rendering this position busy in the way described above. When the operator inserts a plug in the jack 95 the circuit of relay 106 is broken at the contact 104 and the busy condition is removed from this position, but this trunk line is kept busy by the earth connexion over the jack contact 109. The insertion of the plug also energizes the cut-off relay 13 and connects the subscriber's line to the plug. If the desired line is one having a distributing-switch, the calling plug is inserted in a jack 23, the cut-off relay being energized but not the cut-in relay 40. Each position is provided with a call-barring key 180 for use when all the cord circuits of the position are required for manual calls, and with a non-barring key 126 for use at night when one operator deals with all calls. Specification 14,945/12 is referred to.