If you are using plain old telnet (eg, not the telnet support in paclink or airmail) to connect to server.winlink.org, port 8772, to read winlink2000 mail, you need to put a '.' in front of your callsign, to force the telnet connection to use 8bit transparency mode. Apparently this is some old convention that dates back to the early 70s.
bash-3.2$ telnet server.winlink.org 8772
Will map carriage return on output.
Connected to server.winlink.org.
Escape character is '^]'.