Method of transfer of switching order information for transmission of PCM words

Claim 1

In a multichannel time division multiplex system for handling PCM words which has incoming and outgoing links connected to an exchange comprising a first time stage, a space stage and a second time stage wherein during time slots of frames indicated by time slot numbers the PCM words are transferred from the first time stage via the space stage to the second time stage wherein the space stage is divided into a number of file contact planes, each of which has an incoming transfer file connected to an associated switching order unit having register means, and has incoming and outgoing files connected to associated respective substages in the first and second time stage, respectively, and wherein each substage is connected to links associated with the respective substage among the incoming and outgoing links to and from the exchange, so that the number of file contact planes corresponds to the number of outgoing and incoming files from and to any one of the substages in the first and second time stage, a substage in the first time stage and a substage in the second time stage forming part of a common time substage, each furthermore including switching order memories which, for receiving of switching order information, are connected to the respective files outgoing from the file contact planes, the method of transferring switching order information from the switching order units to the switching order memories wherein the switching order information includes in the case when a communication path is to be connected between an incoming channel on an incoming link and an outgoing channel on an outgoing link, a slot number which indicates the time slot allotted to such path, and time substage addresses and channel indices which together indicate the channels, and including, in the case the path is to be disconnected, the substage address indicating the incoming link and the slot number which have been used during the connection, and instead of the channel indices and the substage address indicating the outgoing link, used during the connection, such indices and such an address which cannot be used for any connection, the method comprising the steps of: selecting definite time slots during which only switching order information, and not PCM words, is transferred on the files outgoing from the file contact planes, dividing each of said definite time slots into two portions, storing the switching order information in the register means of one of the switching order units, transferring from the respective register means to the transfer file of the switching order unit, said slot number in each of the first portions of said definite time slots, and reading from the respective register means the substage address indicating the outgoing link and the channel indices in their respective second portions of said definite time slots, decoding the substage address indicating the incoming link during the time slots in which the substage address indicating the outgoing link and the index indicating the outgoing link and the index indicating the incoming channel are read, further decoding the substage address indicating the outgoing link during the time slot in which the index indicating the outgoing channel is read, and connecting during said decoding and during said further decoding in the file contact plane the transfer file to the file outgoing to the time substage the address of which is being decoded.