I was curious what some opinions were on a communications problem that I'm about to have to deal with.
The setup: I need multidrop communications that support star-like and daisy chain at the same time. Distance is on the order 100 feet for the near drops to a max of around 200 yards due to wire/fiber routing. Bit rate can be arbitrarily low - not much to communicate - 300 baud is plenty fast. I need some kind of isolation because the units will be individually powered and separated by such distances. I cannot do wireless of any kind. It has to be wired or fiber.
I do have to worry about collisions and negotiating which node has the floor to send out its information in case more than one ends up with something to send at a given time. And naturally, I'l like things to be as small as possible, low power, and if there was a chip solution that handled all negotiating that would be even better. I'd just throw XPorts at the problem and use network cable except the housing is too tall for my application without using a daughter card. That's possible I suppose.
I kind of like the thought of using fiber because of the inherent isolation / long distance capability but the star configuration thing gets to be a problem as well as the need for a unit in the middle of the string needing to communicate to both directions out. I could do a big loop with fiber I suppose but that adds setup issues - not that big of a consideration since this is a one-time install but I'd prefer to make setup as simple as possible.
Wired adds other issues even though it's easier to make it accept star and daisy chain configurations as well as make adding new nodes trivial.
I was just curious if anyone else had to set anything like this up before and if there were obvious solutions. To be honest, I haven't researched this at all so please don't waste your time researching it for me. I was just curious if anyone had any obvious choices that jumped out at them.
Thanks for any thoughts or help!