I have a 403 when you try and make oubound calls the message in the display read lines busy when they are not and disconnects the call. It is random it can do this 3 or 4 times on a particular line and then it will work on that same line the next time. it does the same thing on all 7 lines randomly. There is no dial access code to get but I have tried putting in a dial 8 acces code and it does the same thing??