This system has been virtually trouble free for many decades. Recently the 2d line of a 2 line system sounds dead when you press the button for a line and a few seconds later goes to a busy signal. I have powered it back up many times with no change. I need to find someone who is familiar with this ancient system to advise me if there is any hope. How can I find someone with some experience with this Nitsuko Onyx VS pbx system? Thanks in advance for any help. Comcast has been out and says it is not their lines. He says there must be a short in the pbx. An analog answering machine , according to him, successfully gets both lines. He suggested a cordless base system would be inexpensive. Any thoughts?