My forte’ is 911, in particular ALI equipment.  I’m searching for an interface specification for Switch-ALI communications provided by dms100’s via the ENH911AS feature.

I know from prior research the switch can talk to the ALI via RS232 or X.25 (in my case, it will be RS232 -> protocol converter -> IP -> ALI).  I don’t really care how a switch admin would configure this particular feature, or really anything about the switch hardware that supports the circuit.

All I’m really looking for is what the ALI should expect in the way of message content/format (pretty sure there are A, W, Q and E type messages, and I suspect there are heartbeats), and how I would parse out the individual chunks of info those messages contain. 

If anyone knows where I might find that type of info, please let me know.