I've been really busy this year with replacing 23 fire alarm panels, networking them together via fiber, and all the paperwork that goes with it. I took one of the old fire alarm control panels (FACP) home with a couple remote annunciators (RAs). I set everything up today and basically t-tapped the the input wire for the annunciator to it and my rs485 to usb and watched the port via terraterm. I had to play with the serial setting and I was able to see what the FACP was sending to the RA, I did the same and discovered that the RA sends "L" back to the FACP to acknowledge troubles, as well as "M" to silence alarms and "N" to reset the FACP.
FACP out to RA FACP in from RA
This is a big step in the right direction, but I do not know how to send from my pc. I tried "send Command" from terraterm but that did not work. I'll have to do some more research after lunch.