SE334924B - - Google Patents

Abstract

1,139,270. Automatic exchange systems. SIEMENS A.G. 20 Oct., 1967 [21 Oct., 1966], No. 47804/67. Heading H4K. Metering pulses subject to distortion on lines 11 to xy are gated to individually associated storage cores K11-Kxy by sampling pulses e (Figs. 1 and 2), these cores being interrogated by doublet pulses a, b occurring just before and just after each alternate sampling pulse e. The results of the a and b interrogations are registered separately on registers E1 and E2 for groups of lines in parallel, the registers being read out serially to produce coincident outputs a1 a2, corresponding to an a, b, interrogation for each line. The outputs al, a2, are put in a store SP by way of leads e1, e2, and are returned one scanning cycle later as signals m1 m2, for comparison with the current a1, a2, signals. The signals m1, m2, al, a2, are operated on by gates S1 and S2 so that if in the order given they exhibit the binary code 011 in the first or last three bit positions then a signal ad is generated to instruct the common metering store to add one to the corresponding subscriber's cumulative meter pulse store. An alternative process of judging the results of interrogation is illustrated in Fig. 3 where the. al, a2 signals produce a signal el for storage and production one scanning cycle later as m1 only if both a1 and a2 are binary ones. If al and a2 are binary ones and the preceeding signals al, a2, were not, i.e. m1 does not exist, then a signal ad to the common meter store is produced. The alternative process requires a faster sampling pulse rate relative to the meter pulse length than is required for the circuit shown in Fig. 1. To eliminate negative impulse interfering voltage on the metering lines diodes D11-Dxy are provided. The decision as to the presence of a pulse may be based on more than two consecutive doublet interrogations