I have a 3 year old Husky mix that I'm potty training. He was never an indoor dog, so never had to signal. With Tiberius I'd take him out every two hours at first, and if I caught him having an accident I'd say 'No' and take him outside to finish. I wouldn't get loud, but would be stern. When he would do on his walks he would get lots of praise and a yummy treat. I also set him up with an area (now he has a crate) for him to stay in when I couldn't watch him. Now he tells me whenever he has to go out, and if I don't hear him right away, he gets one of the cats to start talking..lol