I am working on a project, the door control system I am using is a bit old, and it works through a serial connector on a 4 pin RJ11 line. I am currently trying to wire an old serial wire into its RJ11 wire, so I can get my raspberry pi to work with it. (I am using a USB to serial connector on the pi)
However, the problem is I don't know which wire goes into what. The door controller is one I got was from a friend's deconstruction project. Its a Stanley Access Technologies MC521 controller.
The RJ11 has 4 colors on it, black, red, green, and yellow from order left to right. And has the text RS232 near it. A signal was detected on the red wire when it boots on.