Tools to assist debugging and verifying meter data
Currently supported protocol types are Norwegian HAN and M-Bus.
The electrical interface uses two wires — one master powers multiple meters (typically drawing 1.5 mA each). There is only one master, and the number of meters depends on the available current. Meters have no polarity, simplifying wiring.
Communication is voltage-based from the master and current-based from the meters. Learn more at m-bus.com.
Wired telegrams start with 68h <len> <len> 68h and end with <checksum> 16h.
The header includes c-field, primary address, ci-field, and secondary address.
Wireless telegrams begin with a length byte = total length − 1 and use
c-field, secondary address, and ci-field.
The ci-field is often 7Ah, with data beginning with 2F2Fh after decryption.
Kamstrup compact telegrams (79h) depend on prior 78h packets, not yet supported.
The electrical connections for Norwegian HAN is a reversed M-Bus, the meter acts as master, and receivers act as a slave.
A cable supports only one meter but several receivers can be connected to a single meter.
The meter transmits telegrams at predefined intervals.
The telegrams are of different lengths. The short telegrams with momentaneous power values are sent with seconds interval. The longest
telegram are sent with intervals up to an hour contain all values, momentaneous and accumulated. This is why it may take up to an hour
to read all values from a meter.
RJ-45 connectors use pins 1–2 for HAN communication — never connect directly to an Ethernet port! See manufacturer documentation: Aidon, Kaifa, Kamstrup.
A brief introduction to HAN telegrams.
If you find an error or have a suggestion, please send me an email.
Page version 2025-10-24