... twisted pair 2:different appearance,distnace 3:300/600/1500m, 9items 4:1/4/8/16channels 5:power ... 1: passive Twisted-Pair Video Transmission, control distance 300metres, lightning protection,NA-600A-1: passive Twisted-Pair Video Transmission, control ... distance 600metres, lightning protection.NA-5001B: active Twisted-Pair Video Transmission, AC12, 1A ...