... Jumper is OFFpossition, when press button A on the transmitter, receiver channel A goes on 2 secondsthen goes off automaticaly...Same of ... :[For example 4ch wireless switch] Press 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 ... A/B/D is OFF; Press remote button D,the receiver relay D is ON,the relay A/B/C is ...