Rec. ITU-T V.24 (03/1993) … LIST OF DEFINITIONS FOR INTERCHANGE CIRCUITS BETWEEN DATA TERMINAL EQUIPMENT (DTE) AND ...
FOREWORD
CONTENTS
1 Scope
2 Line of demarcation
3 Definitions of interchange circuits
    3.1 100-Series - General application
    3.2 200-Series - Specifically for parallel automatic calling
    3.3 Circuit failures (electrical)
    3.4 Optional circuits
4 Operational requirements
    4.1 Data circuits
    4.2 Idle periods
    4.3 Clamping
    4.4 Operation of circuits 107, 108/1 and 108/2
    4.5 Interrelationship of circuits 103, 105 and 106
    4.6 Timing circuits
    4.7 Circuit 125 - Calling indicator
    4.8 Usage of circuits 126 and 127
    4.9 Circuit 140 - Loopback/Maintenance Test
    4.10 Interrelationship of circuits 202 to 211
Reference