I think it went GE, Ericsson, M/A-COM, Tyco, Harris. I may not have all the dance partners, nor in the right order.
That sounds close from what I recall.
I know our local power company, Ameren Electric (used to be Union Electric) switched from an analog low band system to EDACS many years ago now and their radios all had the GE symbol on them back then.
I don't recall how long EDACS systems had been on the air when they switched though or if they went to EDACS when it was a brand new system.
Today, Ameren is a multi-state system that is huge. Most of it (if not all now) was converted over to P25 a few years ago. Mostly Harris systems but I'm not sure if they choose Harris for all their systems when they went P25 or not. I know all the systems within my range are Harris now.
They were an EDACS user that used the annoying scanner defeat set of tones at the end of each transmission! I'm sure you heard that before where the repeater plays a set of about 5 or more tones the fall in frequency just before the repeater dropped.
I was always told it was there only to deter the scanner listener and otherwise, offered nothing to the users of the system. The users did not hear the musical sounding tones and I think Uniden and others also had a defeat feature that would ignore the irritating musical tones but early model scanner type radios that offered EDACS support did not offer the option to mute that garbage.
They were probably still Union Electric back in those days. Union Electric was more of a local utility unlike the giant Ameren Electric that bought them out.
They do have a monstrous radio system though when you look at the database page that shows all their systems and not just Missouri or Illinois.
I know they could patch the old Edacs systems together and talk to about anyone but I don't know if they added that full capability when they switched to the Harris P25 systems they are using today.
They also never switched to any of the more advanced Edacs based systems. At least in my area. They remained on a basic Edacs system and used iCalls a Lot back in those days.
With the switch to the Harris P25 system, I don't hear them using any private call features much.