sepcial for IP camera and DVR 1,receiver function inbulit siren ... by remote control . our device cannot supply 12dc power for IP camera or dvr , the device itself is supported ... pairs of interface , one is for I/O,the rest for wired sensor (wired PIR)2.as for the silent/siren button ,we ... differert voice chip .3.our device cannot supply 12dc power for IP camera or dvr , the device itself is supported ...