ES362722A1 - A PROVISION FOR THE CYCLICAL OCCUPATION OF CONNECTION SYSTEMS IN SWITCHING FACILITIES IN SPECIAL TELEPHONE SWITCHING INSTALLATIONS. - Google Patents

Abstract

A cyclically scanned storage matrix has sections storing the state of junctor circuits, one code being used in a storage section to indicate that the associated junctor is free and another code, termed the preference code, being used in place of the one code to indicate that one of the junctors that is allotted as next for use, the preference code being transferred to the next storage section with a "free" code whenever a junctor is seized for use. A ferromagnetic core storage matrix has four planes so that each coordinate position as illustrated in Fig. 1 represents a capacity of four bits. The upper group of matrix rows serve groups of 10 subscribers TG, the rows from 11 on serve as stores for individually associated local junctor circuits HUe, the rows from 21 on serve as stores for exchange line circuits AUe, while row 31 and further rows, if required, serves as a store for an operator's position VPl. The first word of each row is examined by setting a scanner AE2 on the first column and stepping a scanner AE1 over a decoder 2 to read out the matrix row by row. For a subscribers' group the first word of each row indicates if any one of the group requires service. For a local junctor or an exchange line circuit the first word of each row indicates idle or busy state and, if idle, the preference code if that circuit is allotted next for use. The scanner AE1 over decoder 1 synchronously interrogates the circuits TG, HUe, AUe and VPl to effect supervision and update the storage matrix. When a local junctor is required in response to a detected calling condition in the line group stores the scan proceeds to the junctor storage rows to find that junctor the store for which contains the preference code indicating its allottment for use. If, as happens when the exchange is first switched on or due to circumstances such as fault, no preference code is written to nominate a junctor, the scanning cycle proceeds and during the next occurring scanning cycle the rules of seizure are changed so as to select that junctor first discovered with an idle code in its store. The event of seizure causes the preference code to be written into the store of the junctor next found to be idle. Seizure of exchange line circuits AUe may be effected using a preference code to pre-allocate a circuit for seizure in the same manner as with local junctors. The same technique may be employed to pre-allocate operators' positions where a group of such positions is provided.