ANSI C12.21:2006 (R2016)

1 Scope
2 References
3 Definitions and Syntax
  3.1 Definitions
      3.1.1 C12.21 Client
      3.1.2 C12.21 Device
      3.1.3 Table
  3.2 Document Syntax
4 Protocol Details
  4.1 Order of Transmission
  4.2 Layer 7 - Application Layer
      4.2.1 Data Structure
      4.2.2 Protocol Specification for Electric Metering
            4.2.2.1 Request Codes
            4.2.2.2 Response Codes
            4.2.2.3 Identification Service
            4.2.2.4 Read Service
            4.2.2.5 Write Service
            4.2.2.6 Logon Service
            4.2.2.7 Security Service
            4.2.2.8 Logoff Service
            4.2.2.9 Authenticate Service
            4.2.2.10 Negotiate Service
            4.2.2.11 Wait Service
            4.2.2.12 Terminate Service
            4.2.2.13 Timing Setup Service
            4.2.2.14 Disconnect Service
  4.3 Layer 6 - Presentation Layer
  4.4 Layer 5 - Session Layer
  4.5 Layer 4 - Transport Layer
  4.6 Layer 3 - Network Layer
  4.7 Layer 2 - Data Link Layer
      4.7.1 Basic Data Information
            4.7.1.1 Fixed Settings
            4.7.1.2 Variable Settings
      4.7.2 Packet Definition
      4.7.3 Duplicate Packets
      4.7.4 CRC Selection
      4.7.5 Acknowledgement
      4.7.6 Retransmission
      4.7.7 Time-out
            4.7.7.1 Channel Traffic Time-out
            4.7.7.2 Inter-Character Time-out
            4.7.7.3 Response Time-out
      4.7.8 Turn-around Delay
      4.7.9 Collision
  4.8 Layer 1 - Physical Layer
5 Compliance
Annex A - Communication Example (Layer 7 and Layer 2)
Annex B - Packet Transmission Example
Annex C - Service Sequence State Control
Annex D - Modifications and Extensions to C12.19-1997
  D.1 RDATE Type
  D.2 Table 03 ED_MODE STATUS Table
  D.3 Table 07 - Procedure initiate Table
  D.4 Decade 90: Telephone Control Tables
  D.5 History and Event Log Codes
  D.6 Default Sets for Decade Tables
  D.7 Indices for Partial Table Access
Annex E - CRC Examples
  E.1 Trace
  E.2 C Code Example
Annex F - Error Handling
Annex G - Data Encryption Standard
  G.1 Usage
  G.2 Legal Issues
  G.3 Implementation
  G.4 Code Example
  G.5 Trace Examples
Annex H - I Command Operational Description
Annex I - Compatibility
  I.1 Backward Compatibility With Previous Versions of
      the Standard
  I.2 Forward Compatibility With Next Versions of the
      Standard
Annex J - Historical Background
  J.1 Foreword of C12.21-1999

Details the criteria required for communications between a C12.21 device and a C12.21 client via a modem connected to the switched telephone network. The C12.21 client could be a laptop or portable computer, a master station system or another electronic communications device.