[TriLUG] null modem cable?

[Rick DeNatale]

And those RFCs would be?

Actually RS-232 (now EIA-232) predates IETF by quite a few years. 
It's a standard from the Electronics Industries Associations.

The only RTFs which I can find which mention RS-232 in their titles
are RFC 1317 Definitions of Managed Objects for RS-232-like Hardware
Devices and RFC1659 which obsoleted it.

Finding the "Official" EIA/RS-232 standard seems problematical. It's
supposed to be available for purchase from Global Engineering
Documents, but it seems to be well buried. It's probably now only
available as part of some larger document set.

Of course, since the standard is so old, there's lots of non-official
info available about it.