IEC 62056-21 is an international standard for a computer protocol to read utility meters. It is designed to operate over any media, including the Internet. The protocol is used to transfer data between a master computer station and the meter.
The document provides the complete information necessary to develop third-party communications software capable of communication with the meter.
The protocol is supported via the optical IR port COM1 and serial port COM3. The initial baud rate for data exchange is programmable for IEC 62056-21 ports. For the optical port, it can be selected from 300 Bd to 19200 Bd. For port COM3, it can be set to one of the standard baud rates from 300 Bd to 19200 Bd, and to not-standard baud rates 38400 Bd (Z=7), 57600 Bd (Z=8) or 115200 Bd (Z=9). The meter provides a standard data readout of ASCII-coded data with optional baud rate switching.