Source google image: http://4.bp.blogspot.com/-ATQpRMbnt2s/UdmLHe1kIGI/AAAAAAAAIGo/KFaqDvLFLtg/s1600/Sonnerie+command%C3%A9e+par+relais++Commande+%C3%A0+Tr%C3%A8s+Basse+.JPG
Schema électrique sonnette
Source google image: http://4.bp.blogspot.com/-ATQpRMbnt2s/UdmLHe1kIGI/AAAAAAAAIGo/KFaqDvLFLtg/s1600/Sonnerie+command%C3%A9e+par+relais++Commande+%C3%A0+Tr%C3%A8s+Basse+.JPG