Patent GB-191406210-A (GB)
Title: Improvements in or relating to Automatic or Semi-automatic Telephone Exchange Systems.
Inventor: BETULANDER GOTTHILF ANSGARIUS
Filed: 1914-03-11
Granted: 1914-11-05
Abstract: 6210. Betulander, G. A. May 24, 1913, [Convention date]. [Addition to 29,615/13.] Automatic and semi - automatic exchange systems. - Relates to systems of the kind described in the parent Specification, in which a selecting and testing device is temporarily employed to discover an idle intermediate line capable of connecting an incoming calling line to an idle outgoing line of a desired group, the incoming and outgoing lines being then connected to the intermediate line while the temporary selector is released for further service. The present invention enables sets of relays to be used in place of mechanical selectors, both for the selection of the intermediate line and for its connexion to the incoming and outgoing lines. The system is shown in Figs. 3, 1, and 2, which should be placed one above the other in the order named. Only three out of every ten lines or groups of lines are represented. From an inspection of the Figures, it will be seen that by energizing one of the relays 113, Fig. 1, any of the incoming lines 111, 112 can be connected to any of the intermediate lines 114, 115, and that each of the. intermediate lines can be connected by a relay 131, Fig. 3, to one outgoing line 132, 133 in each of the groups I, II, III. In order that an intermediate line may be capable of extending a call, it must not only itself be disengaged, but the outgoing line of the wanted group to which it has access must also be idle. The discovery of an intermediate line fulfilling these two conditions is effected by a selector 120, or 121, Fig. 2, in conjunction with a set of testing-relays 139, 136, 141, Fig. 3. The through connexion is then established by the energization of one of the relays 113, Fig. 1, and one of the relays 131, Fig. 3, and the selector and testing- relays are set free so as to be available for the control of a second selecting-operation in the same group of incoming lines. Two selectors are provided so that two selecting-operations may proceed simultaneously, but means are provided for preventing both selectors from getting access simultaneously to the testing-relays. When a call arrives on an incoming line, the line wires 111, 112 and also the third wire 150 are grounded. The relay 118 individual to the calling. line is energized by a circuit through its upper winding and connects the line to the first selector 120, Fig. 2, supposing this selector to be idle. The relays 126, Fig. 2, and 129, Fig. 1, are now energized over the line wire 111. The relay 129 locks up the relay 118 through a second winding and disconnects the upper windings of all the relays 118, while at the same time it prepares the circuits of the upper windings of relays 119, so that if a call arrives on a second incoming line while the selector 120 is in use, the line is connected by a relav 119 to the alternative selector 121. A relay 127 energized by the relay 126, locks itself under the control of a release relay 128 and locks up the relay 129 over a wire 170. The line wire 112 is now connected at the contact 179 to the bottom relay 125, Fig. 2, of the selector 120. This relay becomes energized and energizes the corresponding relay 124, which locks itself up and keeps the relay 125 energized at the contact 183. The numerical impulses are now transmitted as current interruptions in the line wire 112. The first interruption unlocks the bottom relay 125, and at the termination of the impulse the next pair of relays 125, 124 is energized. In this way the relays 125, 124 are energized in pairs, a fresh pair being energized at the termination of each impulse. The last impulse is prolonged, and before it ceases the line circuit 111 is also interrupted, de-energizing the relay 126, so that ground is connected over the contacts 186, 187, 188, 190 to one of the group-determining wires 191, energizing a relay 141, Fig. 3, corresponding to the wanted group of lines. (The relay 172 of the alternative selector 121 is energized in a branch circuit 189, Fig. 2, and opens its contact 188, preventing this selector from getting access to the relays 141 until the selector 120 has finished with them. If the relays 126 of both selectors should be de-energized simultaneously, the relays 172 would at first both be energized, each opening the other's circuit. The relay 172 of the selector 120 in this case de-energizes again immediately, but the relay 172 of the selector 121 remains energized over a locking-contact 206 and only de-energizes when the selector 120 has finished its business.) The relay 141 connects the testwires 156 of the lines of the wanted group to the upper windings of a series of test-relays 136, individual to the various intermediate lines. The test-relay corresponding to any intermediate line is now energized either if the line itself is engaged (the lower winding being energized in this case through a test wire 154 and a contact 155 of a connecting-relay 131), or if the outgoing line to which it has access in the wanted group is engaged (in which case the upper winding is energized through the test wire 156 and a contact 157 of a relay 131). The first intermediate line available for effecting the desired connexion is therefore the first line of which the corresponding test-relay 136 is deenergized, and a relay 139 corresponding to this line is energized over the back contact 194 of the test-relay and its own back contact 195. The relay 113, Fig. 1, for connecting the calling line to the selected intermediate line, and the relay 131, Fig. 3, for connecting the intermediate line to the corresponding outgoing line of the wanted group, are now energized as follows. It will be seen that the lower windings of the relays 113 are connected between vertical wires 147 and horizontal wires 146, while the lower windings of the relays 131 are connected between vertical wires 149 and horizontal wires 148, so that the energization of any one of these relays is determined by the completion of a circuit through a particular vertical wire and a particular horizontal wire. One of the wires 148, 147 is connected to battery by the energization of the relay 139 individual to the selected intermediate line; one of the wires 146 is connected to ground bv the relay 118, Fig. 1, of the calling line; and one of the wires 149 is in a branch from the grounded group-determining wire 191. The appropriate connecting-relays 113 and 131 are therefore energized as soon as an intermediate line has been selected. The relays 113, 131 lock themselves in a circuit including their respective upper windings and wires 150, 151, 152, and remain energized until the connexion is released. In the meantime the release relay 128, Fig. 2, of the impulse-counting selector 120 is energized over the wire 203 by the energization of a relay 143, Fig. 3, and this brings about the unlocking of all the relays concerned in the operations described, except the connecting - relays 113 and 131.