NWG/RFC# 736 MRC 31-OCT-77 23:28 42213 Telnet SUPDUP OptionNetwork Working Group Mark Crispin Request for Comments 736 SU-AI NIC 42213 31 October 1977
1. Command name and code.
SUPDUP 21
2. Command meanings.
IAC WILL SUPDUP
3. Default.
WON'T SUPDUP