1745 (ISO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOIHA OPIAHW3ALIM HIO CTAHIAPTW3AIHN .ORGANISATION INTERNATIONALE DE NORMALISATION Information processing --- Basic mode control procedures for data communication systems Traitement de I'information -Procedures de commande pour transmission de donnees en mode de base First edition - 1975-02-01 ISO 1745-1975 (E) Ref. No. ISO 1745-1975 (E) UDC 681.327.18.01 Descriptors : data processing, data transmission, control procedures, control characters. Price based on 19 pages 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 IS 1745 was drawn up by Technical Committee ISO/TC 97, Computers and information processing, and circulated to the Member Bodies in May 1973. It has been approved by the Member Bodies of the following countries : Australia Japan Switzerland Brazil Netherlands Thailand New Zealand Turkey Canada Poland United Kingdom Czechoslovakia Egypt, Arab Rep. of U.S.A. Romania France South Africa, Rep. of U.S.S.R. Hungary Spain Yugoslavia Italy Sweden Bodies of the following g countries expressed disapprovat of the The I Member [ document on technical grounds : Bulgaria Germany This s International Standard and replaces ISO cancels Recommendation R 1745-1971, of which it constitutes a technical revision. @ International Organization for Standardization, 1975 : Printed in Switzerland CopyrighintemationalOrganizaioor Standardization ted without license from IHS Not for Resale CONTENTS Page 0 Introduction 1 0.1 General 1 0.2 2 Communication phases 1 Scope and field of application 2 2 1.1 General 1.2 3 Assumptions 2 Definitions of the transmission control characters 3 3 Message formats 4 4 3.1 General rules 3.2 Information messages 4 3.3 Forward supervisory sequences 5 3.4 Backward supervisory sequences 5 4 Description of phases 'L5" Phase linkage 6. 4.1 8 4.2 Phase diagrams 10 4.3 Recovery procedures Description of use of the transmission control characters 13 5 Annexes (not part of the Standard) 16 A Definitions Extensions of transmission control functions B 16 using DLE sequences 16 c Alternate positive acknowledgement option iii Copyright International Organization for Standardization Not for Resale