NTERNATIONAL STANDARD Tso 2628 INTERNATIONAL ORGANiZATION FOR STANDARDIZATION -MEKIyHAPOHAS OPrAHW3ALHS HO CTAHIAPTH3ALMH.ORGANISATION INTERNATIONALE DE NORMALISATION Basic mode control procedures --- Complements Firstedition-1973-06-01 UDC 681.14 ! Ref. No. ISO 2628-1973 (E) Descriptors : data processing, data transmission, control procedures, character sets, codes. Pricebased on8pages FOREWORD ISO (the Internationa! 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 bytheISOCouncil. International Standard ISO2628 was drawn up by Technical Committee ISo/Tc 97, Computers and information processing, and circulated to the Member Bodies in May 1972. It has been approved by the Member Bodies of the following countries : Australia Ireland Spain Belgium italy Sweden Japan Switzerland Czechoslovakia Netherlands Thailand Egypt, Arab Rep. of New Zealand United Kingdom France Portugal U.S.A. Germany South Africa, Rep. of U.S.S.R. NoMemberBodyexpresseddisapprovalofthedocument. @ International Organization for Standardization, 1973 Printed in Switzerland ISO 2628-1973 (E) INTERNATIONAL STANDARD Basic mode control procedures - Complements O INTRODUCTION International Standard. However, those systems implementing the functions described in this International A data communication system may be considered as the set Standard and conforming to ISO/R 1745 and ISO 2111, of the terminal installations and the interconnecting must followthese recommendations. network that permits information to be exchanged. A data link comprises terminal installations connected to 2 REFERENCES the same network,operating at the same speed, in the same ISO/R 1745, Basic mode control procedures for data code. Any "store and forward" delay or intermediate data communication systems. (At present under revision.) processing separates data links.Any system is constituted ofoneorseveral datalinks. Iso 2111, Data communication - Basic mode control procedures - Code independent information transfer. The information transfer in a data link is monitored by data link control procedures where some characters,selected CCITT Recommendation V24, Function and electrical within a coded character set, are given particular meanings characteristics of circuits at the interface between data accordingto the transmissionphase and are used for various terminal equipment and data communication equipment. purposes such as to delineate information, to reverse the direction of transmission, to ask questions, to answer, etc. 3 RECOVERYPROCEDURES This International Standard defines complements to the basic mode and its extensions : 3.1 General 1)Recovery procedures These recovery procedures are system guidelines which System guidelines are given for the use of timers, should be used by all stations, as applicable. However, it is counters,etc.; recognized that the detailed method of station mechanization, absolute value of timers, etc., may vary 2) Abort and interrupt procedures with applications and communication facilities. Definesabort procedures which are always In some cases, these recovery procedures can only detect initiatedbythemasterstation,and interrupt the error condition and then notify the operator or the procedures which are always initiated by the slave processor program, or both. In more sophisticated cases, station; automatic recoveryispartially orcompletelypossible.In other cases, only operators can perform the