4pin TTL as endstop

How does a 4pin TTL sensor PCB get implemented in the context of the typical 3pin RAMPS endstop inputs?
eg:
[www.aliexpress.com]

I suspect this is a stupid question, but everything I google is avalanched by products and a distinct absence of useful information.

The connections are marked on the back of the PCB. On one that I got the pins are

TTL
ADO
+5V
GND

I am not sure what ADO is but you only need the other three - TTL is the main output but I don't remember if it needed active high, active low or was reversible.. This unit seems to work well but I think it will need a mechanically and electrically quiet printer as there is no high pass filtering.

Mike