GB/T 17215.646-2018 Electricity metering data exchange—The DLMS/COSEM suite—Part 46:Data link layer using HDLC protocol
GB/T 17215.646-2018 Electricity metering data exchange—The DLMS/COSEM suite—Part 46:Data link layer using HDLC protocol
Basic Information
Scope
This part of GB/T 17215.6 specifies the data link layer for connection-oriented, HDLC-based, asynchronous communication protocol sets. To ensure that the data link layer services specifications are consistent for both connection-oriented and connectionless operation modes, the data link layer is divided into two sub-layers: the logical link control sublayer (LLC sublayer) and the media access control sublayer (MAC sublayer). This part supports the following communication environments: -- Point-to-point and point-to-multipoint configurations; -- Dedicated and switched data transmission devices; -- Half-duplex and full-duplex connections; -- Asynchronous start/stop transmission with 1 start bit, 8 data bits, no parity check, and 1 stop bit. At the same time, the following two special protocols are defined: -- Transparently transmitting the PDU portion of the service user layer received from the server to the client. The server-side service user layer can send its PDU in fragmented form to the data link layer, and the data link layer can hide the fragments for the client; -- Reporting events by sending UI frames from the slave to the master station. Appendix B explains the data model and the role of the protocol in data exchange in electricity meters.