Hi, I've a Sentient M-link 4 channel cctv, bought with two cameras, which up till now have worked OK. Recently I decided to add a 3rd camera, but upon connecting it all the 3rd screen does is flash on & off showing brief pictures of what the two other cameras are showing. I bought a new sim cable for this camera, the camera itself is given by a friend who has just moved house & replaced his cameras with better ones. I could understand if the 3rd screen was flashing with a picture of what the 3rd camera was pointed at, but not the flashing screen showing alternating pictures of what the other two cameras are showing.? Any solutions/tips etc. Thanks, K.