4
I assume-
ADE came from logic basic key operated panels & each new model became more complex than the previous ?
Texecom was cheap Pir maker which expanded the range into a vertias then employed a 3rd party to engineer the premier ?
Pyronix was a cheap Pir maker, (mid 80's be 5 x 2019 prices) expanded out to making other sensors, sounder & then low end panels, in the end purchasing a proper panel maker
I'd also assume if you had the ability to produce intruder alarm controls you would make a lot more doing something different ?