This product is part of the light module of a kit that allows you to integrate 2 Railroad Crossings together with 2 side-on Detectors and 1 crossing bell all controlled by the Lamplighter DFL unit. 

It comes in 9 versions, HO, N and O Gauge and each of these with or without a power supply or with a power adapter to suit your needs.

There is absolutely no programming nor soldering required.  The 3 wires from the detectors and crossing bell need to be attached to the DFL unit using screws built into it.  It couldn't be easier.

The fibers are inserted into two "chimneys".  Each can hold either a 1.0mm fiber for the HO RR Crossings or 0.75mm fiber for the N RR Crossings.

When ordering the DFL unit select

1. Whether you want a power supply (9V) (extra cost of $10) or not (in which case you can use your DC bus from your layout which must be >7V with center positive wiring into the power jack connector provided in the kit) and you are done.