Scantronic 6400?

I have a Scantronic alarm in the house we bought, we have no idea what the pin number is, nor how to operate. Now several lights on the control panel are flashing and number 8 bulb is saying that the battery needs changing. How can I get this problems sorted out?? I have rang several companies and all they want to do is turn it off. Yesterday it started bleeping and we could not turn it off. Help!