Have a customer with one of these antiquated systems. I don't normally work on these but they were desperate to get up an running with their phone lines again. The system had lost programming and defaulted so no Trunks were assigned and only X201 would receive calls. Anyways, I got CO's assigned to keys so at least they can make and answer calls. What I need to figure out is how to make all extensions ring on all CO's. Right now, only the reception desk (X201) gets an audible ring. Also, If the button assigned to CO1 is pressed and then you press any of the other CO buttons, it doesn't release the first one you pressed and they would like it to release when the select another CO.