So, I managed to get a terminal - an old WYSE 160.  It mostly works pretty
well as a serial port gizmo, with a couple of problems.

1.  The terminal doesn't appear to support CTS/RTS handshaking; it supports
DSR/DTR.  (Either that, or this is a DCE/DTE line naming convention thing,
and it *should* work, but...)
2.  If I enable DSR/DTR handshaking, whenever the terminal tries to handshake,
it ends up causing getty to respawn - I suspect NetBSD is seeing it as a
break.
3.  There seems to be no way to indicate that a given terminal should
have xon/xoff handshaking enabled.
4.  ssh seems to unconditionally disable xon and xoff!

As a result, there appears to be no reasonably standard way to set this
terminal up to work as a reliable console device.  If it's set for hardware
handshaking, it blows up, and if it's set for software, I can't ssh from
the window it opens.

Has anyone got clever suggestions?  My preferred solution would be to get
hardware handshaking working, but that appears to involve debugging a setting
I haven't figured out yet.

-s