M-bus

The M-Bus system is used in plants with 
M-Bus capable counters e.g. heating -, cooling and warm water, electrical and gas meters, when the data must be readout and stored in a central place. The stored data can be readout depending upon the central unit over optical or serial interface or via telephone modem.
 
Main applications:

• Long Distance and block heating systems
• Commercial buldings
• Single and multi family houses 

With the M-Bus a 2-wire line connects a central unit (master) with the participant devices (Slaves; e.g. heat meters). It serves both for the power supply of the peripheral devices, as well as for data exchange between central unit and terminals. The central unit requests the participants over a tension-modulated signal successively for sending its data blocks. These answer with modulated data telegrams. Also the devices can be individually queried.

The M-Bus system of the company SONTEX corresponds to the relevant standards and is compatible after the suggestions of the working group CEN TC 176/WG4. This was tested already several times in mixed  installations.