Patent GB-191312651-A (GB)
Title: Improved Circuit Arrangements for Telephone Systems.
Filed: 1913-05-30
Granted: 1914-03-19
Abstract: 12,651. Siemens & Halske Akt.-Ges. July 8, 1912, [Convention date]. Automatic exchange systems.-In systems in which lines to be selected are connected in groups to the selectors, there are as many different means of access, which can be taken into use as required, to a selector, as there are groups of lines connected to the selector. For example, in a 200- point connector serving the lines 200-399 and having two sets of wipers and two test relays, one set of wipers and one relay is rendered operative w h e n connexion is made from the second level of a group selector, the other set of wipers and relay being used when connexion is made from the third level. This arrangement is shown in Fig. 3, in which if a group selector GW extends connexion to a connector W over the contacts g, the connector operates in the usual way under the control of its test relay P<2> to select a line in the group G, but if the selector extends connexion over the contacts g<1>, a relay R in the test lead is energized and substitutes the test relay P<3> for the relay P<2> so that the connector establishes a connexion in the group G'. Second arrangement, Fig. 4. The selection of the group at selector W need not be effected, as shown in Fig. 3, at the selector immediately preceding this, but at one nearer the calling station. In the system shown in Fig. 4, when connexion is extended through a second selector IIGW<1> in the 4000 section of the exchange, the selector W operates in the usual way and extends a call over the wipers a<2>, b<2>, c<2> to the group G, but when connexion is extended through a second selector IIGW<2> in the 5000 section of the exchange, the relay R is energized and substitutes the wipers a<3>, b<3>, c<3> for the wipers a<2>, b<2>, c<2>, so that a call is made in the group G<1>. Third arrangement, Fig. 5. Instead of providing two sets of wipers, the single set of wipers may be given an additional ten steps by local impulses when a call is to be made in a certain group. When a connexion is made over the contacts g by the group selector GW, the selector W is positioned by the line relays A, B and vertical and rotary magnets H, D in the usual way, but when a connexion is made over the contacts g<1>, the relay R is energized so that when the relay B, energized by the switching-impulse, has energized a self-locking relay U and has again released its armature, a selflocking relay F is energized and connects an interrupter to the rotary magnet D. After ten impulses, the contact w<10> is opened by the rotation of the shaft, which is then further rotated by the impulses sent by the calling subscriber. Fourth arrangement, Fig. 6. If the selector W is at a distant exchange, the additional ten impulses may be sent over a two-wire junction from an impulse sender J at the originating exchange. The group selector GW is provided with an additional wiper f, which prepares the circuit of a relay B' when the group selector is raised to the first, third, fifth, &c. level. When a connexion is made over the second, fourth, &c. level, the connector W is operated in the usual way, but when a call is extended over an odd level, the relay B<1> is energized in parallel with the relay B by the switching- impulse, and moves the side-switch SS into its third position, in which the rotary magnet Di of the impulse sender J is intermittently energized, and its contact i is connected to the wiper a so that ten impulses are sent to the distant exchange and rotate the connector through ten steps prior to the receipt of the last set of selecting-impulses. Other methods of sending the additional current impulses are referred to. Fifth arrangement. When selectors having sets of wipers, which must be unlocked before operation, are used, relays in the different incoming test leads may be used to unlock different sets of wipers.