I have checked line clarity using linecheck over this medium. I expected it to be completely transparent, but it is not. However, the only bad character seems to be 255. The ˜/.term/termrc.telnet I use (the .telnet is the name of the term connection, see above) contains:
baudrate off escape 255 ignore 255 timeout 600
Perhaps it could be improved by diddling, I am getting a throughput of only about 30k cps over a long-haul connection through a slow firewall. Ftp can move about 100k cps over the same route. A realistic baudrate might avoid some timeouts.