IEC62056绿皮书，包括通信协议、通信规程等内容。This fifth edition of the "Green Book" includes the specification of the communication protocol layers based on:- IEC 62056-42, Electricity metering- Data exchange for meter reading, tariff and load control- Part 42:

this part of IEC 62056 standard, HDLC protocl standard-this is part of IEC 62056 standard, HDLC protocl standard