The BIM M111 or the BIM M115 are members of Siemens instabus EIB BCU - family. They are especially designed as small modules for piggyback use and can be fitted directly into PCBs. The modules contain all functional parts of a EIB - BCU with the exception of shift register for the serial synchronous interface. Additionally access to such microcontroller ports as Reset, PLMA, or Port A is possible. These ports are directly accessible by the user. Additional pins for the connection of an external programming button and a LED are available. For applications with the need of longer 'Bus Buffer Time' the BIM allows to connect an additional capacitance at bus voltage level.