This part of IEC 62056 specifies the DLMS/COSEM 3-layer,connection-oriented HDLC based communication profile.
IEC 62056-7-6:2013 Referenced Document
IEC 62056-21:2002 Electricity metering - Data exchange for meter reading, tariff and load control - Part 21: Direct local data exchange
IEC 62056-42:2002 Electricity metering - Data exchange for meter reading, tariff and load control - Part 42: Physical layer services and procedures for connection-oriented asynchronous data exchange
IEC 62056-46:2002 Electricity metering - Data exchange for meter reading, tariff and load control - Part 46: Data link layer using HDLC protocol
2013IEC 62056-7-6:2013 Electricity metering data exchange.The DLMS/COSEM suite.Part 7-6: The 3-layer, connection-oriented HDLC based communication profile