Patent GB-904463-A (GB)
Title: Improvements in or relating to arrangements for seeking, selecting and setting up free transmission paths in coupling panels in a telecommunication system
IPC: H01H67/24
Filed: 1959-01-15
Abstract: 904,463. Automatic-exchange systems. SIEMENS & HALSKE A.G. Jan. 15, 1959 [Jan. 15, 1958; June 2, 1958], No. 1577/59. Class 40 (4). Apparatus for selecting free transmission paths between a particular inlet and a free outlet of a desired group of outlets comprises a path-seeking network corresponding to the transmission system, wherein free outlets of the chosen group of outlets are marked with a first potential and all busy outlets with a second potential arranged to over-ride said first potential at the respective coupling points of the outlet coupling multiple. One of the coupling points where the first potential is not over-ridden is then selected and so determines the transmission path to be used. The coupling points are multipled in columns, as shown in Fig. 1. In the rows of stage B the coupling points are connected individually to outlets, the outlets Zl-Zk associated with the first row forming part of an outlet group R1. The outlets Z(l-1)k+1-Zl-k form part of the last outlet group Rp. Several of the remaining figures use a convention in which, for example, contact lkajk represents the first contact of the coupling point in stage A at column j, row k; the inlet Tj represents the inlet connected to column j. The transmission network is shown in Fig. 2 and a path-seeking network in Fig. 3. A call allotter (not shown) actuates contact y1 and a marker (not shown) actuates a contact, such as rp, corresponding to the outlet group to which connection is to be made. Resistance earth is thus connected to row selector ZW in respect of each idle outlet. In the case of a busy outlet the appropriate lead to ZW ix marked by battery - U from the inlet end. Row selector ZW selects a row and connects column selector SW to this row, whereby one outlet is selected. As the column of the B stage is thereby determined the path-seeking action is concluded. The path bj, 2kajk, 2kbkl, Fig. 3, corresponding to the speech path shown in Fig. 2, is completed so that busy potential over-rides earth potential at rectifier 1Gkl in any subsequent pathseeking operation. Fig. 4 shows a modified path-seeking network in which busy inlets are marked by battery. In such a case relay SK operates to connect earth as a busy marking to the coupling- point selector KW. In a further modification, crossed-coil selectors of the type described in Specification 797,913 are used. The call allotter and marker operate contacts yk to connect the network of busying wires to the intermediate line selector ZLW. The marker also operates contacts such as dl associated with the desired outlet group Dl, so connecting resistance battery to ZLW. If the coupling point kbkl is in a column in which no coupling point is yet in use, this potential is applied to the appropriate lead in ZLW to indicate a free intermediate line. If, on the other hand, a coupling point in this column is busy earth is applied through rectifier Gk to over-ride the resistance battery, so indicating a busy intermediate line. ZLW then chooses one of the available intermediate lines and as contacts dl have determined the row, a single coupling point has been selected. A coupling panel outlet already busied by a connection extending through another coupling panel such as Sl-k has " busy " earth applied through rectifier Gl-k to over-ride " free " potential applied through resistance Wl-k. Rectifier Gk prevents " free " potential - U at terminals of holding coils HAk, HBk disturbing ZLW. Minor modifications are described.