How far can a TI link cable go? USB can only go 30m, Ethernet is 100m, how much can a TI link IO cable go?

I'd say it's okay up to around 5 meters.
Getting longer is hard because it's fairly low-voltage signaling, and there's no differential logic involved (both lines are 5V TTL, pulled up, whereas both USB and Ethernet use differential signaling in twisted pairs). On the plus side for long runs, the TI link protocols are fairly low-frequency and don't push much current around.

It really depends on your environment, but I'd say 5 meters or so should be safe in most cases with a standard unshielded cable.

Is there some sort of repeater i can buy or make? I want to run a connection cable 150m to my friends house.

I've been able to push about 10 meters, but yes, longer than that won't work. Tom, why don't you build two CALCnet to gCn bridges and use globalCALCnet between your houses? I presume you both have internet.

Nope but i do have a network switch that we play on. I ran 2 100m ethernet cables to his house with a repeater in the middle so he can connect to the net switch. Can you use gCn with a network that doesn't have internet access?

Yes, you just need a gCn server running on one of the computers; it's a Python program. I don't think I've publicly published the server implementation before, but I'd be happy to share it with you. Please note that it only works for CALCnet-enabled programs and games like CALCnet Chat 1.0 and Obliterate, not for general link-port programs.

No general link-port programs But still, better than nothing

However, how far would a shielded link cable get me to?

Not much farther than a non-shielded cable, sadly. The length limit is due to voltage drop over distance and the fact that the two conductors interfere with each other, so you could probably get some extra distance by individually shielding the two signal wires, but you'll still have voltage drop-off over distance.

I too have extended my link cables about 10m with several 5ft extension cables. I would've tried more but that's all I had at the time.

Going along with the networking idea, this would be a perfect use for my network-aware linking program, tinc: http://www.cemetech.net/forum/viewtopic.php?t=8089&highlight=tinc

With tinc you run it on two different computers connected to the calculators with some type of Graphlink cable (any type supported by ticables, eg, Blacklink, Graylink, Parallel link, USB silverlink). On one computer you would have tinc listen for connections and on the other computer you would have tinc connect to the first computer. Every byte that a calculator sends gets sent to the other computer over the network and then written to the calculator.

Unfortunately, I don't have networking capabilities in tinc yet (it works only locally over stdin/stdout at the moment), but I'll try to add networking when I have some free time. In the meantime, you could try using tinc with netcat and named pipes, as I did in my demo on my thread about tinc.

um, why would you want to do this?