... ,image transmission3)Full-duplex hands-free call ,clear audio and video4)Visiting key wake up call ,standly power-sawing ... sleep5)Unclock door and alarm function6)CE, ROHS,FCC available7)83 effective communication ... channels,frequency-hopping technology,super eror- correcting capability ,so the conversation is very stable8)Untrashort bulit-in antenna design , ...