Applies to telecontrol equipment and systems with coded bit serial data transmission for monitoring and controlling geographically widespread processes. Covers asynchronous data transmission with half duplex and duplex link protocols operating with window size one for message transfers. Covers requirements for data transmission in telecontrol systems, high data integrity and data consistency, short telecontrol transfer time, support of bit oriented data transmission, quantified rating of data integrity, quantitative requirements for data integrity in telecontrol systems, quantified rating of transmission efficiency, transmission protocol specifications, physical layer, link layer, link service classes provided, dialogue procedures, standard frame synchronization and formats.BS AMD 8113 RENUMBERS THIS STANDARD