Electricity metering - Payment systems - Part 52: Standard transfer specification (STS) - Physical layer protocol for a two-way virtual token carrier for direct local connection

IEC 62055-52:2008(E) specifies a physical layer protocol of the STS for transferring units of credit and other management information between a client (typically a HHU) and a server (an STS-compliant electricity payment meter), typically over a direct local connection. It is complementary to the application layer protocol specified in IEC 62055-41 and should be used in conjunction with that standard. It is intended for use across a range of payment meters developed by different manufacturers and to ensure compatibility between these products and other client devices. It specifies a client/server communications protocol.