Patent GB-715931-A (GB)
Title: Improvements in or relating to non-numerical telecommunication switching arrangements using relay line-finders
Inventor: SPIECKER FRIEDRICH
IPC: H04Q3/00
Filed: 1952-07-23
Abstract: 715,931. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. July 23, 1952, No. 18688/52. Class 40 (4) A large group of incoming lines is connected to equipment common to all the lines over three stages of all-relay line-finders. As shown in Fig. 1, a large or super-group of lines Tn is required to be connected to any one of a number of 'sets of selecting relays WR1 ... 60. Each super-group comprises five groups TnGr 1 ... 5 each group such as TnGr1 being divided into sub-groups TnUGr1 ... 4. Each sub-group has access over relays LK to ten interstage links 1ZLv. The interstage links of the various sub-groups of a group have access to twenty interstage links 2.ZLv each link 1.ZLv having access to two links 2.ZLv. The links 2.ZLv associated with all the groups have access in common to 60 sets of selecting relays WR1 ... 60 each link 2.ZLv having access to three sets of selecting relays. In the event of less than 60 sets of selecting relays being necessary, the full 20 links 2.ZLv are retained but some of these have access to only two sets of selecting relays. Detailed operation.-Line relay AR1 operates to the incoming loop over Tn1 and brings up Ka1 in the line circuit in series with R1 and An1 in the first control circuit LO1. Ka1 short circuits its high resistance winding thereby preventing any other Ka relay in the sub-group from operating at this time. Each set of selector relays such as WR1... 3 has a busy relay O1 ...03 operated when the set of selector relays is in use. The contact chain 17o1, 18o2, 19o3 determines the order in which these are taken into use by interstage links 2.ZLv. If all three of this group are busy a circuit is closed in control circuit VHO1 for relay C11 (i) associated with the link 2.ZLv1 and similar relays in control circuits VHO2-5 are also operated thus marking such links as 2.ZLv1 busy if they have no access to free selection relay sets. This relay is also operated over C11(iii) if the link itself is busy. Links 1.ZLv also have similar relays C1 ... C10 associated with them which are operated (e.g. over C1(iii)) if the link is busy or if the corresponding relays associated with the two links 2.ZLv to which it has access are also operated (e.g. over C1 (i)). The order of choice of links 1.ZLv is determined by the contact chain Qv1 . . . 10 the first relay Qv whose corresponding relay C (1 ... 10) is back, operating to designate the link. The choice of the two links 2.ZLv is determined by a chain Q11, Q12, the latter or the former operating according as C1 1 is or is not operated. Relay Plo1 operates in series with this chain shortcircuiting its high resistance winding to prevent the operation of similar chains in the control circuits Lo2 ... 4. Assuming C1, C11 and O1 are unoperated so that Qv1 and Q11 operate, Plo1 brings up Q1 which operates K1<SP>1</SP> to couple the incoming line Tn1 with the link 1.ZLv1. Likewise K11 and K21 come up in series with Cwr1 to couple link 1.ZLv1 to link 2.ZLev1, and link 2.ZLv1 to the selection relay set WR1, respectively. A holding circuit is now complete for the coupling and busy relays in series with O1 and TR1. The latter releases AR1 and An1 the latter initiating the release of the control circuits.