Alpro's interlock controller is designed specifically to be used as part of an access control system, with emphasis on the control of doors within that system, which need to interlocked. That is to say, when one door is closed and locked the other door can be opened and operated. The interlock controller is a dual voltage unit operating on either 12/24v DC and offers flexibility with pluggable terminal blocks and nylon stick on mountings, which allow for expansion of the units capabilities.