Patent GB-146079-A (GB)
Abstract: 146,079. Automatic Telephone Manufacturing Co., (Assignees of Nelson, M. L.). June 30, 1919, [Convention date]. Automatic exchange systems; party-line systems.-In a code signalling arrangement for calling party-line stations in an automatic exchange system, the code to be signalled is determined by a plurality of distinct selective operations, such as the dialling of two extra digits. The invention is shown applied to a connector H, Fig. 1, which establishes connexion with the wanted line and subsequently effects the operation of the codeselecting switch B, and also as applied to a ring- back switch D, Fig. 2, for reverting calls. The wipers 40, 41 of switch B, or the wipers 115, 116 of switch D, are adjusted by the last two digits so as to determine the connexion of battery to certain contacts of the code switches C, C<1>, and thereby control the application of the ringing- generator to line. The set of relays I, common to switches B, D, serves only to ground intermittently the leads 61, 62 and may be replaced by an ordinary interrupter. Operation of connector H to select wanted line. The vertical and rotary magnets 7, 20 are operated in known manner under control of the line relay 2, release relay 5, and series relay 8 to select the wanted line. If this is idle, the busy relay 21 is not energized, and relay 19, which was energized in parallel with the rotary magnet 20, completes a circuit over the lower winding of relay 24, which locks up over its upper winding and prepares circuits for the switch B. Operation of code-selecting switch B. The next series of impulses is repeated by the line relay 2 over contacts 10, 15, 18, 37, 31, wire 45, contacts 38, 39, relay 35, to the vertical magnet 36, which raises the wipers 40, 41 to the desired level. When these impulses cease, relay 35 de-energizes, so that the final set of impulses passes from wire 45 over contacts 38, 42, 46, 47, relay 48, to the rotary magnet 49, which rotates the wipers 40, 41 to the desired set of terminals of the code switch C. Relay 48 energizes a relay 51 which locks up and by earthing wire 60 starts the interrupter 1, which consists of a set of relays arranged to interrupt one another's circuits so as to ground intermittently the wires 61, 62, &c. Assuming the code number called to be 22, the wipers 40, 41 are connected to the 3rd, 6th, 15th, and 18th contacts in the path of arm 63, which, together with arm 64, is rotated by magnet 54. At the end of the last set of impulses, relay 48 closes a' circuit from the interrupter I over wire 61 for the magnet 54, which moves the arms 63, 64 on to their first set of terminals, thereby closing a circuit for a relay 66, which connects up the ringing-relay 70, so that succeeding impulses over the wire 61 energize in parallel the magnet 54 and the relay 70. Ringing-current is thus connected to the called line at each impulse over wire 61, until the arm 63 reaches the first contact connected to wiper 40, when the relay 80 is energized to disconnect the ringing-relay. When the arm 63 reaches the next contact, ringing is resumed at each impulse until the arm 63 reaches a contact connected to wiper 41, whereupon relay 66 is short-circuited and disconnects the ringing-relay 70. The relay 66 remains de-energized until the arm 63 reaches the starting-contact in the second half of its travel, whereupon the same cycle of operations is repeated. When the called subscriber answers, the ring-cut-off relay 78 is energized, completes the talking circuit, and disconnects the switch B. Operation of ring-back switch D, Fig. 2. When this switch is taken into use over a certain level of a group selector, the line relay 100 and release relay 101 are energized. The vertical and rotary magnets 113, 118 are operated in known manner by the two last sets of impulses to cause the wipers 115, 116 to make connexion with the de- &ired set of terminals of the code switch C<1>. The relay 117 in series with the rotary magnet 118 energizes a relay 122, which locks up over the off-normal contact 124, so that when relay 117 deenergizes at the end of the impulses and the line relay 100 releases when the calling party replaces his receiver, a circuit is closed for a relay 126, which disconnects the line relay 100 from the calling line and connects the latter to the ring-cut-off relay 136 and to the armature 138 of the ringing- relay 139. The relay 126 also energizes relay 140, which causes magnet 54<1> to step around the wipers of the code switch C<1>, and relay 143, which connects the ringing-relay 139 in parallel with magnet 54<1>. The relay 139 is then energized intermittently according to the code number of the wanted line, in the same manner as the relay 70, Fig. 1. When the called party replies, relay 136 energizes, disconnecting the ringing-current, and energizing the release magnet 149, whereby ground is cut off the release trunk 109 so that the group selector is released. Microphone current is supplied to the party-line through the line relay of the group selector.