[comp.unix.ultrix] 19200 autobaud under Ultrix 3.0

grr@cbmvax.UUCP (George Robbins) (06/08/89)

...
> 	This combination of entries allows the local DTE to autobaud
> 	correctly from 9600 to 1200 baud on an incoming call on the
> 	Telebit.
...
> 	TrailBlazers are supposed to be able to work at 19200 baud,
> 	but I can't seem to get the DTE/TrailBlazer combination to
> 	autobaud to 19200.  I changed the /etc/gettytab to be:

I'm not sure which you mean by "auto-bauding".  The standard autobauding
selected by the "A" terminal type probably only switches up to 9600,
unless the old BSD coding has been changed.  The default "autobauding"
you get when typing characters at the wrong baud rate causing a break
to be sensed isn't all that reliable.  Switching baud rates up to
19200 by explicitly sending breaks works fine.

Much depends on how you set up the trailblazer.  For simplicity's sake,
there is a lot to be said for fixing the interface rate.  This works
quite well, when you are doing ascii stuff with X-on/X-off enabled or
uucp, with protocol support enabled.  It would probably lose big time
with the "we don't believe in no flow control" emacs crowd.  I don't
know how well RTS/CTS handshake works with Ultrix - I'm not inclined
to be optimistic.

I run mine with a variable interface rate, with the default rate set
to 1200, one break required for 2400, another for 19200.  I let the
modem worry about 9600/19200 rate conversion when slower sites call.
This requies that the modem be carfully set up, since the default is
to try to ""talk" to the host at the interface rate the hosts last
talked to it.  This is often inappropriate but using S50=254 (not
documented in older manuals) makes PEP default to 19200 on incoming
calls.

I should admit that I'm still using a heavily patched version of
Ultrix 1.2 uucp (under 3.0) since I had real problems getting shared
lines to work on a DMF32 port.  I may break down and try the 3.0
uucp one of these days to see what's fixed.

Also be warned that, at 19200 with more than one Trailblazer active,
you're going to get occasional "silo overrun" messages on your console.
These seem fairly harmless, but you may want to keep the Trailblazers
on their own interface.
-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)