The bases have been designed to enable detectors to be plugged in without any need for force and have a "one way only" fit.
The standard base contains no electronic parts which could be damaged during installation.
Several types of relay base are available: an auxiliary relay base
and two types of EOL (End-of-Line) relay bases designed for circuits
with supply voltages of between 9 and 18V DC and 16 and 33V DC.