Subject: Re: Serial setup.
To: None <netbsd-help@NetBSD.ORG>
From: Ty Sarna <tsarna@endicor.com>
List: netbsd-help
Date: 03/02/1995 21:47:23
In article <2F56121A@ms-mail.datastorm.com>,
John Maier  <JohnAM@datastorm.com> wrote:
> 
> I don't know how many times I've gotten into this when I was in tech. 
> support.
> 
> Serial 101:

[yes, I know all that] "DTE rate" is common usage today for "DTE-DCE
speed", as perpetrated on us by modem manuals. "Line speed" is common
useage for the modem-modem rate.

> So what does baud rate have to do with DTE-DCE speed? Nothing!(typically)

Since you're nitpicking me, I'll nitpick back that baud != bps. :-)

> >Supras allow this (&C1), as do most others, I think.
> 
> No, What I mean is, if you were to send 'AT&C0' (carrier goes high). 
>  Someone dials in, hangs up, some modems pulse CD low then go back high. 
>  But there are some rare cases where the modems keep CD low, after hang-up, 
> without you sending an 'AT&C1' to the modem.  The later behavior, typically, 
> depends upon the &D setting.  Typically most people set &D to 2 (AT&D2) but 
> factory defaults, and other factors don't always dictate this (when in 
> doubt, consult the documentation).

The AT&C1 behaior is availible on most modems, and is what is wanted for
Un*x.  So set it and be happy.  If you don't like the &C0
behavior, don't set &C0.  ("Doctor, doctor, it hurts when I do this...")

The rest of your message seems to be agreeing with me -- that it is
possible to effectively lock the DTE rate (or DTE-DCE speed, if you
prefer).  If you're modem can't be set to power up at your desired DTE
rate (most can), you may need to change it before starting getty, but
there shouldn't be a problem after that -- set getty, uucp, and whatever
other programs you're using to always use 19200 (or whatever) and you
shouldn't have a problem. 

Maybe I'm missing something here, but I don't see what the problem is.

-- 
Ty Sarna                "I thought you were wrong before, but compared
tsarna@endicor.com       to now you were right" -- Exit 57