... 1) self lock model eg.KL-402Press remote button A first time, the receiver relay is on, press button A again , ... B/C/D.3) interlock modelPress remote button A, the receiver relay A is on, the relay B/C/D is off.Press ... remote button B, the receiver relay B is on, the relay A/C/D is off.Press remote button C, the receiver relay C ... learn code and fix code(eg.kl-400)12V 6-channel remote control switch