UniSMART2 is a communication module, pre-mounted & configurated on new gas meters or as a retrofit module for already installed gas meters of Apator Metrix. The robust Unismart2 has smart solid-state sensors for volumetric measurement of values of the mechanical index of the diaphragm gas meter. The sensors detect possible return flow and secure against “false pulses”. Index values and events as tampering and overflows are logged and communicated following 868 MHz Wireless M-Bus (cooperates with devices working in OMS standard), T-mode, security mode 7, profile B in the M-Bus telegram. A lifetime of battery mounts up to 20 years, communicating every 5 minutes. Communication is compliant with German BSI specifications. For retrofit modules on installed gas meters, Apator has developed a special tool for easy and fast installation.