公开(公告)号：DE1277921B

公开(公告)日：1968-09-19

申请号：DEJ0028395

申请日：1965-06-22

Applicant: IBM

Inventor： CARTHEW JOHN ROBERT ,  LOIZIDES EDWARD ,  MITTA LOUIS ALBERT

IPC: G06F3/00 ,  H04Q11/04

Abstract: 1,043,330. Code converters. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 27, 1965 [June 23, 1964], No. 22546/65. Heading G4H. A code converter includes a store storing a plurality of data characters each represented in a plurality of codes, comparing means for identifying the set of representations associated with a character to be converted, and means for reading out from the identified set the representation of the character in the desired code. In a first embodiment (Figs. 1-4, not shown), a number of time slots in a delay line store each store a character in each of four codes, each such coded representation being preceded by two bits identifying the code. Each such representation and its code identifier are compared in turn, serially by bit, with the representation and identifier of the character to be converted until equality is found. The code identifier of the desired code is then compared, serially by bit, with the identifiers in the rest of the slot until equality is found when the representation following the current identifier in the store is passed to the system output. Here " the rest of the slot " means the preceding or succeeding part of the slot depending on which part the desired code representation is in, as determined by comparing the two identifiers. Two taps, one slot length apart, are provided on the delay line to enable the appropriate slot portion to be obtained. The system is time-division-multiplexed between a number of other units, characters being transmitted parallel by bit. In a second embodiment (Figs. 5-6, not shown), each time slot stores one character in two codes A and B, first in code A, then in code B, and then in code A again. The input character is compared with the store contents until equality is found when the following character in store is passed out. In this way conversion either way between codes A and B is performed. Dummy bits can be inserted in the case of codes of different bit lengths, or each slot can be broken up into 2(2 ) + 1 character sections, where m and n are the numbers of bits in the longer and shorter codes respectively.