Re: Serial console setup

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Fri, Dec 23, 2016 at 10:46:19AM -0500, Greg Troxel wrote:
> 
> Are you saying that the console device itself will refrain from output
> if either DSR or CD is not asserted?   I can see the point of DSR but
> requiring CD for a console seems non-helpful.

The serial port is meant to control a modem. I've seen several
systems where you could dial-in to the console and it was essential
that the console would wait for CD :)

Saying that, I doubt that a regular serial port of a PC-type machine
requires it, but for low-level console it's still under BIOS control.

The other issue is of course automatic RTS/CTS "flow control", and again,
that's something the BIOS can have configured and is ignored by the
low-level code (so, it's not cleared).


Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."