The bus terminal is used for connecting the bus line to EIB devices such as flush-mounted bus couplers, couplers and 4-fold connectors as well as for looping or branching of the bus cable When connecting the bus cable, the correct polarity should be ensured. Reverse polarity of the connections leads to one or more of the devices not functioning. Due to the reverse polarity protection built into the EIB devices, no damage occurs