GO! is a generic tcp/ip connection.
But super-limited bandwidth, you're charged for any modern style app's heavy overheads
Think back to when going from 1200 baud to 2400 was a big deal.
The GO! apps are just designed to make more efficient use, not waste the bandwidth, take advantage of store-and-forward rather than timing out with an error when there are delays in the high latency connection.
Any text-based protocol is fine, email used to be like that, but images
need to be relatively low-res, small and well compressed.
Get to know the Linux
CLI and Pine and you're all set.