DSC Maxsys PC4020/PC4401 driver

[bigdude]

Attached is a driver for the DSC Maxsys PC4020 panel with a PC4401 module attached for serial communication. While the panel is very full featured and extremely expandable, the PC4401 component is a little lacking. I don't know if the driver will end up helping anyone else, but its the panel I have in my house and I was unwilling to replace it.

Note that this driver is heavily derived from jrlewis' IT-100 driver. Most of the credit for it should rightfully go to him.

Posted version: 0.30