Patent GB-1089896-A (GB)
Title: Translator arrangement
IPC: B60L50/13
Filed: 1965-02-12
Abstract: 1,089,896. Automatic exchange systems. STANDARD TELEPHONES & CABLES Ltd. Feb. 12, 1965 [Feb. 13, 1964], No. 6170/65. Heading H4K. In a system in which the directory numbers of at least some of the subscribers are different from their equipment numbers, the number of a wanted line is applied to a first translation field which simply determines whether a translation is in fact necessary and, if it is, the number is applied to another translation field wherein the translation is obtained. This method of translation is applicable to cross-bar systems of the type described in Specifications 963,329, 946,263, wherein each final selector frame has 96 subscribers attached thereto so that it will be necessary for the other 4 subscribers per 100 to be connected to an auxiliary frame and thus equipment numbers different from the directory numbers will be required. PBX lines are also connected to the auxiliary frames, as are lines requiring some special class of service. The number to be translated is compared sequentially with all the possible numbers. First translation field (Fig. 2, not shown).- This comprises a condenser matrix cd1 having two outputs connected respectively to the " 0 " and " 1 " sides of a bi-stable circuit so that an indication "no translation required" or  " translation required " is immediately given. The inputs 1 to n of the matrix are connected through a diode or resistor matrix decoder to a register NAE which receives a directory number e.g. dialled digits, or an equipment number e.g. in the case of malicious call tracing, in the form of a 2 out of 5 code. Second translation field, directory to equipment number translation (Fig. 3).-This comprises a condenser or ferrite core matrix MM having translation outputs vt and indicia outputs vt<SP>1</SP>. The latter indicate whether the row being scanned pertains to: a directory number e.g. row 1 has an indicia II; an equipment number e.g. row 2 provides the equipment number of the directory number in row 1 and its indicia is 00; an equipment number of a PBX line e.g. rows 4, 5, 6 relate to the three lines of a PBX directory number located in row 3, indicia in each case 00; or special code indicia 01 or 10 (see later). There is one matrix MM for each set of numbers having the same thousands digit. Assuming that a registered number is a directory number, a translation is required and that its thousands digit is 1, then an input gate is opened by the conditions br0, spl and nal respectively and the number is transferred from the first translator's register to the second translator's register NA. The number is applied to one input of a comparator CP. Scanner DA, EXS starts and the contents of each row are read-out, one by one, in the form of a 2 out of 5 code for the three translation digits supplied over vt and in binary code for the indicia supplied over vt<SP>1</SP>. When the outputs of MA and MM are identical CP delivers an output which, in conjunction with an indicia signal from D1, sets a bi-stable circuit ba. The scanner steps on to the next row, which provides the equipment number corresponding to the justcompared directory number, whereby bi-stable circuit bb is set and the contents of the row are read into an output register NE. The free/busy condition of the subscriber is determined from magnetic core store TO and if he is free, the number is transferred to a marker MQ. If the directory number concerned is a PBX number and if the first line is busy as indicated by TO, the scanner steps on and the equipment number of the second line of the PBX group is supplied to NE and so on until a free line is found. In any case, when the scanner sets on the next row having the indicia 11 all the circuits are reset and translation is complete. For certain directory numbers, the thousands digit will not be the same as that for the corresponding equipment numbers and rows 7, 8, 9 supply an example of this. The indicia 01 provided by row 8 causes the registration of the required thousands digit e.g. 0 in register ME. When the 3 digit equipment number is read-out from row 9, the free/busy condition is determined from a store TO associated with the thousands " 0," the store TO of the thousands " 1 " being disabled. The row associated with indicia 10 corresponds to a special service number and this is recorded in store CS. Second translation field equipment to directory number translation (Fig. 4).-The same matrix and scanner are used as before but the input/ output circuitry is modified. The equipment number supplied from the first translation field is stored in register NE1, bi-stable circuit br being set to its " 1 " state for this type of translation. During scanning the directory number first read-out is stored in MT1. The following equipment number is then compared in CP1 with that in NE1, and if equality is found the stored directory number is transferred to output register NA1. If the thousands digit of the directory and equipment numbers is different, the hunt through the translation field is fruitless. However the ten translation fields operate in parallel, that one corresponding to the thousands digit of the incoming equipment number having its bi-stable circuit bd set to " 1 " and the other remaining in the " 0 " state. Consequently in one of these other translators when the scanner sets to row 8, the corresponding thousands digit is recorded in MT2 and this number is compared with the thousands digit in NE1 by means of CP2. If the 3 digits provided by row 9 also agree with three in NE1, then the contents of MT1 are transferred (dotted connections) to NA1.