Consider a show where we want to fire aerial shells ranging in size from 3 inches to 10 inches in diameter. According to NFPA 1123 we must keep mortars at least 70 feet from the audience per inch of diameter. Our 3 inch mortars must be located at least 210 feet from the audience and our 10 inch mortars must be located at least 700 feet from the audience.
Why should we put all our 3 inch mortars back at 700 feet where our 10 inch mortars are located? They're gonna look pretty small from that distance.
Instead, we will opt for a system that allows for mortars to be spread out over a large area.
Twisted-pair wiring
The system utilizes RS485 to allow for a large firing area. When I demonstrate my system, some people are surprised to learn that a single (twisted-pair) wire connects to all the SmartRails. This is a technique called daisy chaining . So, even though we can have many SmartRails in the system, and they can be spread out over a large area, the total amount of wiring required is quite small.
A total of 1000 feet of (24 AWG twisted-pair) wire at a total cost of $45 ( from Jameco Electronics is more than enough.
Why not wireless?
I do wireless digital communications on my day job. I have absolutely no doubt that I could design a wireless system that has the range and reliability of my current wired design. However, it would be more expensive and would only save me the trouble of running 1 cheap (twisted-pair) wire.
If there were a real benefit to wireless I would do it. I'm not going
to do it just for fun though.