Patent GB-1262224-A (GB)
Title: Improvements in or relating to translator units for telephone exchanges
Inventor: BELLEC CHRISTIAN LE
IPC: H04Q3/54
Filed: 1970-06-26
Abstract: 1,262,224. Automatic exchange systems. C. LE BELLEC. 26 June, 1970 [30 June, 1969], No. 31205/70. Heading H4K. A translator comprises at least three circulating synchronous stores, means to compare first part of a directory number with designations stored in a first of these stores and upon a match being found to read out from that store the identity of a further of the stores in which a full translation of the direction number is located, and means operative subsequently to said first means to compare a second part of the directory number with the designations stored in the first store and upon the detection of a further match to read out the contents of the synchronized location in the identified store. The arrangement shown can translate from directory to equipment number and vice versa. The further stores each include parity check circuits (Fig. 2, not shown) connected to both inputs and outputs of the delay lines and upon the occurrence of a fault send a signal to a central station which can selectively change the content of the store and/or switch out this store and switch in a stand-by store. A directory number to be translated is received from a common control (not shown) over a line 112 in binary coded decimal form and is entered, the three most significant digits in a register 15 and the three least significant in a register 12. The content of register 15 is recirculated and compared at 18 with the content of store 22 which is a recirculating magnetostrictive delay line store. Upon coincidence an associated address is read out to an address register 27 identifying one of thirty stores such as 29, (having the same construction as and being synchronized with store 22) uniquely identified by the three most significant digits. Stored along with this address is a class of service signal the use of which is not detailed. The address is decoded at 27 and partially enables an AND gate such as 28 1 . Subsequently the least significant digits in register 12 are recirculated and compared with the contents of store 22 and at the moment a match is detected a bi-stable 30 is set causing the enabled AND gate to gate a translated equipment number from the corresponding location in the identified store store such as 29 1  to the common control. To translate from equipment number to directory number, the equipment number is entered in a register 38. The contents of this register are recirculated and compared in each of a set of comparators 431, 432 etc. with the contents of the stores 29 1  etc. with which they are individually associated. One comparator responds marking a corresponding line to a coder 48 and to an OR gate 44. The coder produces the address of the store in which the match was found and the OR gate gates a time signal from a clock driven counter 51 toaregister 49 to identify the time and thus the particular storage location involved. The contents of the register 49 must be recirculated through a subtract one circuit 53 to take account of the fact that certain gate circuits operate in an order designed for directory to equipment number translation. The resultant number in register 49 is subsequently compared by comparator 54 with the content of counter 51 and upon co-incidence the least three significant digits of the required directory number are gated at 55 to a register 32. The coded address in register 48 is subsequently compared with the addresses in store 22. Detection of a match sets flip-flop 30 causing the content of counter 51 to be gated to register 49. During a subsequent cycle it is again compared with the content of counter 51 by comparator 54 a match causing the three most significant digits to be gated from store 22 via gate 58 to a register 35. The directory number now in register 35 and 32 is gated to central control.