I am trying to wire up several Haas CNC machines (very large machines that are used to machine metals and plastics) to a serial server. The "server" will most likely be a Digi PortServer TS 8:
This device (and other similar devices) has RJ-45 ports to connect serially to your host. What I need to know is, how long of a cable can I use before the signal degrades at 115kbps speeds? Also, what type of cable should I get? Should I go for a high-grade category 6 cable? A shielded cable versus unshielded? I have an opinion on this matter, but I'm looking for someone who has either implemented this before and knows the limitations or someone who has actual data to show what is the right stuff to use.
My problem is some of the machines will not be located near the serial server (up to 100' away). I need to know whether I can do this with one serial server or if I need two. If I get two, the cables will be around 10' to 30' (no more than 50').