telnet(1) on OpenBSD
The text dbbdd3ca0ab6, as OpenBSD 2.8, OpenBSD 2.7 shipped it.
user interface to the TELNET protocol
Flags it lists
-
-8 -
-E -
-F -
-K -
-L -
-X -
-a -
-b -
-c -
-d -
-e -
-f -
-input -
-k -
-l -
-n -
-output -
-r -
-x