GB841949A - Registration of calls in telecommunication exchanges - Google Patents

Abstract

841,949. Automatic exchange systems. STANDARD TELEPHONES & CABLES Ltd. June 28, 1957 [July 4, 1956], No. 20701/56. Class 40 (4). Ferric cells are connected individually to associated signal channels and are operated by signals on said channels, and reading equipment is provided for ascertaining the state of the cells. The invention is applied to a metering system in which a subscriber's metering pulse operates a ferro-magnetic or ferro-electric cell. The cells are arranged in a matrix which is scanned to detect operated cells. When an operated cell is detected, scanning is halted and one is added to the associated subscriber's metering store on a magnetic drum. General description, Fig. 1.-Each subscriber's metering lead 1 is connected to a ferrite cell 2, the cells being arranged in a matrix 3 with ten columns and 100 rows. A magnetic drum 9 has ten storage tracks 10, each with 100 register sections. Clock pulses scan access switch 4 having 100 cells 11. When a cell 11 is scanned it applies a reading pulse to all the cells 2 in the corresponding row of the matrix 3. If a cell 2 has been operated by a metering pulse the next reading pulse produces an output pulse in the appropriate column wire of the matrix to operate the corresponding column circuit 12. Scanning by circuit 7 is suspended and the appropriate reading head 16 reads the number stored in the subscriber's meter section of the register track corresponding to the energized column circuit into an adder 15. The adder adds 1 to this total and after one revolution of the drum detected by revolution counter 13 the sum is returned to the register track and scanning is resumed. If two metering pulses are delivered to the same row of the matrix 3 the operated column circuits 12 are dealt with in turn. In the event of a metering pulse being split by a scanning pulse the adder 15 is prevented from operating twice by a detector 18. The cells and matrix may be of the type described in Specification 760,048 and the access switch may be driven in the manner described in Specification 813,580. Detailed description, Fig. 2. When the cell 2 has received a metering pulse the next reading pulse applied to the row containing that cell produces an output pulse to set the related column trigger CT1. A clock pulse p, occurring between successive sections on the magnetic drum, opens gate 19 to set relief trigger RT1. CT 1 operates trigger MO whereupon RD, SC and RP also operate. Trigger SC suspends scanning of the access switch 4, starts revolution counter 13 and opens gate 14, Fig. 1. RT1 connects reading-and-recording head 16 associated with the first register track 10 to gate 14. RD then causes the number read from the track to be entered in adder 15 which adds one to this number. At the end of the register section another clock pulse p restores RD and after a complete revolution of the drum the revolution counter sets W, which causes the total in the adder 15 to be sent to the head 16 and registered in the subscriber's section. W restores RP. At the end of this section a clock pulse restores CT and W followed by RTl. If all CT triggers are normal, MO restores and at the end of the drum revolution RD restores SC and scanning resumes. If, however, two or more cells in the same row have received metering pulses so that two or more triggers CT have operated, then the operated column circuits are dealt with one by one, the gates controlling relief triggers RT2, RT3, &c. being dependent on non-operation of the column triggers CT1, CT2, &c. In such a case, after the first registration of a metering pulse MO remains operated and the process repeats for the next operated column circuit. Split metering. The duration of a metering pulse is greater than the duration of the scanning cycle so that a single metering pulse may operate the same cell 2 twice. So that double recording shall not take place each register section has two check elements such as are described in Specification 744,352, in which marks are placed when the register is taken into use. detector 18 operates when either mark is detected. The marks in the first check element of all sections are erased at intervals during one revolution of the drum. The marks in the second check elements are erased at staggered intervals so that one of the two marks persists for longer than the duration of a metering pulse. Specifications 744,352, 760,048 and 813,580 are referred to.