The BDL168 can be used as an autoreversing unit for return loops.
One of the BDL168 Detection Sections is connected to the non-reversing area, with the balance of the detection connections being made within the reversing area.
Here is a wiring example:
Note that an auto-reverse section can only use detection sections that are contained in a BDL168 zone that is correctly set up for auto-reversing.