In message <200211011402.gA1E2oA12666@guild.plethora.net>, Peter Seebach writes
:
>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.
>

The easiest thing might be to wire a custom rs-232 plug...

When a terminal is hard-wired to a machine, DTR from the terminal goes 
to CD on the machine.  When DTR drop, it therefore looks like carrier 
has dropped on a modem.  Setting CLOCAL in gettytab will disable that, 
I believe.  Hmm -- MDMBUF seems to do exactly what you want.

XON/XOFF is, I think, on by default; it's controlled by IXOFF.  See 
termios(4).

		--Steve Bellovin, http://www.research.att.com/~smb (me)
		http://www.wilyhacker.com ("Firewalls" book)