ISO 12172:2003

Contents
1. Introduction
    1.1 Purpose and Scope
    1.2 Applicability
    1.3 Bit Numbering Convention and Nomenclature
2. Telecommand Data Routing Service Overview
3. Segmentation Layer: Standard Data Structures and
    Procedures
    3.1 Overview of the Layer
    3.2 Standard Data Structures Within the Layer
         3.2.1 Frame Data Unit
         3.2.2 Telecommand Segment
    3.3 Standard Procedures Within the Layer
         3.3.1 Sending End Procedures
         3.3.2 Receiving End Procedures
4. Transfer Layer: Standard Data Structures and Procedures
    4.1 Overview of the Layer
    4.2 Standard Data Structures Within the Layer
         4.2.1 TC Transfer Frame Format
         4.2.2 Command Link Control Word Format
    4.3 Standard Procedures Within the Layer
         4.3.1 Frame Delimiting and Fill Removal Procedure
         4.3.2 Frame Validation Check Procedure
         4.3.3 Command Operation Procedure
Annexes
A Data Routing Service Acronyms and Terminology
B Data Routing Service Specification
Figures
2-1 Telecommand System
3-1 Orientation of the Segmentation Layer
3-2 Telecommand Segment Format
3-3 Example of the Segmentation Procedure
4-1 Orientation of the Transfer Layer
4-2 TC Transfer Frame Format
4-3 Command Link Control Word Format
B-1 TC Data Routing Service Elements
Tables
4-1 Interpretation of the "Bypass" and "Control Command"
     Flags

ISO 12172:2003 specifies the common requirements which define the data routing service of a spacecraft telecommand. The intent of this document is to provide a common framework within which space agencies may implement compatible future spacecraft telecommanding systems.