We recently rescued a Shepard mix puppy, she is 4 months old. We would like to get a dog door, she was house trained when we got her, she will go to the back door when she needs to go out. But she does not bark to let us know she needs to go out just sits there, if we dont catch it in time she will have an accident. Night time is the big problem, since she does not alert us in any way she needs to go out. We are looking into dog doors but we need one that the cats will not go out, my older cat will not go out but the kitten tries to get out all the time. Has anyone used an electronic pet door? What brand and what is your review of it? Does it keep in the pets you don't want out? I am afraid the kitten will piggy back with the dog going out and then maybe getting stuck outside.