It's been awhile since I worked on one of these and this one was given to me by a company that was going out of business. When you power it up the fan comes on, the red led lights on the backplain, and the red and green leds light and go out on the two port cards. I plugged extensions 14,15,16, and 17 into the port cards and dialed those extension numbers from a system phone and no answer. If the port cards are bad that's not a problem but I don't want to buy one and find out something else is wrong. There is not alot of demand for these things in my area and I don't want to have parts laying around that I can't get rid of. Any tips or suggestions would be greatly appreciated.