telnet.netkit(1) on Linux
The text a0b6936f015f, as Debian 3.0 (Woody) shipped it.
user interface to the TELNET protocol
Flags it lists
-
-4 -
-6 -
-8 -
-E -
-L -
-S -
-a -
-d -
-e -
-input -
-l -
-n -
-output -
-r