Interface converter


  • Transparent conversion of M-Bus interface to USB interface
  • Readout up to 20 M-Bus slave devices
  • Short circuit protection of M-Bus line
  • Galvanic isolation up to 1kV DC
  • LED indications On, Rx, Tx
  • Automatic set of data rate and format
  • Plug & Play installation
  • Power supplied from USB port
  • Compatiable with Windows and Linux Operating Systems
  • Driver for virtual serial port


MM20-USB is interface converter intended for transparent readout and power supply of M-Bus slave devices. Converter is powered from USB port and galvanically isolated from the M-Bus line. LED indications show power supply presence, data transmit and receive. Data rate and format adjustment is performed according to M-Bus slave device. Converter is designed to withstand short circuit on M-Bus line. Drivers are installed automatically, if for some reason drivers are not recognized you can download them here.


MM20-USB is suitable for installation and service of M-Bus slave devices. In combination with a laptop, it is suitable for the local setting and reading of heat, water and electricity meters, and other devices that communicate according to M-Bus protocol. Converter acts on M-bus line as standard M-Bus master device which can sustain up to 20 M-Bus slave devices.


M-Bus interfaceM-Bus master, up to 20 M-Bus slave devices, transparent protocol, data rate 300-9600bps;
Connection: pluggable screw terminal 5mm, 2.5mm2
M-Bus portquiescent current: 0-30mA, short circuit: 50-70mA with restart function, line voltage: 30.5V ± 5%, internal resistance <100 Ohm
M-Bus line length> 12km@300bps, > 4km@2400bps, > 1km@9600bps cable JYSTY nx2x0.8
Overvoltage protectiontranzorb on M-Bus line
USB interfaceUSB 1.1 and USB 2.0 standard; Connection: USB (type B)
Data rate and formatAutomatic, according to M-Bus slave device
LED indicationsOn, Rx, Tx
Galvanic isolation1kV DC
Power supplyFrom USB port – no additional mains adapter is required
Operating temperature-20 do 75°C
Dimensions90 x 43 x 20 mm


MM20-USB10337M-Bus interface converter for transparent readout of up to 20 M-Bus slave devices.

*Minimum functionality kit needs to include the device and an appropriate USB cable. Please note that all accessories are sold separately.

Buy from distributor


CB-USBAB-2M21473USB Cable Type A/B 1.8~2m

Product Documents