GB1409316A - Routing designation assembly for use in telecommunications - Google Patents

Abstract

1409316 Automatic exchange systems COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATION CIT-ALCATEL 18 Oct 1972 [19 Oct 1971] 48081/72 Heading H4K A routing translator comprises two sets of co-ordinate matrices the first of which is effective to analyse the first a digits of a dialled number, the second of which is effective to use the result of the analysis to mark an associated group of outgoing trunks and both of which utilize plug-in modules to denote active crosspoints. The successive digits of a dialled number are directed in turn by a register ORN (Fig. 3) to the matrices MA1, MA2, ... MA4 whereby one of AND gates ET1, ... ETn is marked. For example the number 4867-causes row H1 in each matrix to be marked due to the plug-in diodes shown so that gate ET1 is enabled. As a consequence row L1 in a designation matrix MDF is marked with negative potential. In the event that there are free trunks available in the direction (or rather the bag of equipment corresponding to the direction) indicated by the marking which appears on column F3 courtesy of the shown plug-in diode, transistor T3 conducts and so brings-up relay RF3 which applies a seize signal over lead DF3 to the relevant trunk group. All trunks busy for any particular direction is denoted by a potential on leads OF1, ... OF m which is sufficient to hold off the associated transistor T1 ... Tm whereby transistor TEF is enabled following the initiation of a translation process as denoted by the actuation of contact ca so as to signify the busy condition over output lead DEF. Alternative routing is effected with the aid of portion FD of the designation matrix. The additional resistors RD ensure a higher threshold for turning on the transistors T1-Tm so that only if a first choice route is unobtainable e.g. by all trunks busy marking on say OF1, will the second choice route be selected, e.g. by operation of T3 in the considered use of a route direction marked by row L2 of the designation Third and further choice routes may be provided by the use of additional matrix portions and bias resistors (Fig. 6, not shown). PBX hunting.-One of the columns CI of a matrix, e.g. MA4, may be permanently marked so that one of its rows, e.g. H2 is permanently marked. In the considered case therefore gate ET2 is permanently marked for the fourth digit of a number and will thus respond for any dialled number in the range 3270 to 3279. In a form of abbreviated dialling in which one digit serves two or more digit places, the column in the first digit place corresponding to this digit is diode strapped to all the rows of the matrices to be served by this one digit thus ensuring that route choice is effected only by one or more subseequent digits. The register arrangements for recognizing a reduced number of digits are not described.