Subject: Re: urgent repost: serial port problem
To: None <, mouse@Rodents.Montreal.QC.CA>
From: Ross Harvey <>
List: port-alpha
Date: 04/01/1999 15:32:03
> From Thu Apr  1 08:10:30 1999
> Date: Thu, 1 Apr 1999 10:54:37 -0500 (EST)
> From: der Mouse  <mouse@Rodents.Montreal.QC.CA>
> To: jamie <>
> Cc:
> Subject: Re: urgent repost: serial port problem
> >> Everything works fine, until I hooked a modem up to the serial port.
> >> Not long after netbsd boots the DTR light comes on on the modem &
> >> also the RD & TD lights stay on.
> This sounds to me like the infinite-echo problem: both the modem and
> the host are echoing characters, so as soon either of them sends
> anything they start jabbering at one another.  If either end produces
> an error (eg, a modem command error) this only fuels the fire.
> >> Once netbsd has finished booting I can <sometimes> connect to a
> >> remote modem, but when the connection is established this modem just
> >> pumps garbage to the remote one.
> Connect how?  And what sort of garbage?

Umm, what were you going to use this modem for?  The 3000 model which I
think you said you were running doesn't have the usual NS16550-type com
port that almost all other alphas have, and for which NetBSD/alpha-current
has a really nice driver.

Instead, it's one of the few systems where we call into the SRM console
for serial I/O .. so, it's not interrupt-driven, input involves polling,
and output is via busy-wait, plus a crude call into the console that locks
the whole system.

It doesn't support much if any of the usual modem control signals, either.

So .. forewarned is forearmed...