3275 NTERNATIONAL STANDARD (TSO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAyHAPOIHAS OPrAHW3AIMS HO CTAHIAPTW3ALWW.ORGANISATION INTERNATIONALE DE NORMALISATION Information processing -- Implementation of the 7-bit coded character set and its 7-bit and 8-bit extensions on 3,81 mm magnetic tape cassette for data interchange Traitement de I'information -- Materialisation du jeu de caracteres a 7 élements et de ses extensions a 7 et 8 eélements pour I'échange d'information sur cassette de bande magnetique de 3,81 mm de large First edition - 1974-11-01 ISO 3275-1974 (E) UDC 681.3 Ref. No. ISO 3275-1974 (E) Descriptors : data processing, data transmission, character sets, information interchange. Price based on 1 page Not for Resale FOREWORD IsO (the International Organization for Standardization) is a worldwide federation of national standards institutes (isO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the iso Council. International Standard ISO 3275 was drawn up by Technical Committee ISo/TC 97, Computers and information processing and circulated to the Member Bodies in July 1973. Ireland Australia Sweden Belgium Italy Switzerland Canada Japan Thailand Czechoslovakia Nethertands Turkey France New Zealand United Kingdom Germany U.S.A. Poland Hungary Romania U.S.S.R. No Member Body expressed disapproval of the document. International Organization for Standardization, 1974 Printed in Switzerland Copyrightlnternational Oorganization for Standardization Not for Resale working permitted without license from IHS ISO 3275-1974 (E) INTERNATIONAL STANDARD Information processing -- Implementation of the 7-bit coded character set and its 7-bit and 8-bit extensions on 3,81 mm magnetic tape cassette for data interchange 1 SCOPE AND FIELD OF APPLICATION processing or data communication system or in part of such a system. This International Standard specifies the implementation of the 7-bit coded character set and of its 7-bit and 8-bit extensions for the interchange of data on 3,81 mm RECORDING FORMAT magnetic tape cassette. According to 1SO 3407, the data to be interchanged are recorded serially by bit and by character. Each character is 2 REFERENCES located in a byte of eight bit-positions along the track. The bit-positions in a byte are numbered from 1 to 8 in order of ISO 646, 7-bit coded character set for information processing interchange. recording. ISO 2022, Code extension techniques for use with the 7-bit The following diagram summarizes these concepts : coded character set. byte is0 3407, Information processing - 3,81 mm (0.150 in) .32187 654321876.. Bit-positions : . magnetic tape casse tte for information interchange, 32 bpmm Forward tape motion : (800 bpi), phase encoded.1) Resutting recording direction : 3 DEFINITIONS 5 RECORDING OF 7-BIT CODED DATA 3.1 magnetic tape: Tape which wil accept and retain magnetic signals intended for input, output and storage Each 7-bit coded character is recorded in bit-positions 1 to purposes on computers and associated equipment. 7 of a byte; bit-position 8 is recorded with value ZERO. The relationship is as follows : 3.2 track : A longitudinal area on the tape along which a series of magnetic signals may be recorded. Bits of the 7-bit combination : 0] b b6 b５ b4 b3 b² b1 3.3 byte : A bit string that is operated upon as a unit, and Bit-position whose size is independent of redundancy or framing in the byte : techniques. 7 6 5 4 3 2 3.4 code; coded character set : A set of unambiguous rules 6 RECORDING OF 8-B