libmbus: M-bus Library from Raditex Control (http://www.rscada.se) 
libmbus is an open source library for the M-bus (Meter-Bus) protocol.
The Meter-Bus is a standard for reading out meter data from electricity meters, heat meters, gas meters, etc. The M-bus standard deals with both the electrical signals on the M-Bus, and the protocol and data format used in transmissions on the M-Bus. The role of libmbus is to decode/encode M-bus data, and to handle the communication with M-Bus devices.
For more information see http://www.rscada.se/libmbus