Home page logo

nanog logo nanog mailing list archives

Re: Laptop with reverse VGA
From: Jay Ashworth <jra () baylink com>
Date: Tue, 21 Feb 2012 09:48:21 -0500 (EST)

----- Original Message -----
From: "Jake Khuon" <khuon () neebu net>

I think the form-factour is already there. I have a Motorola Atrix
smartphone. It's available with a laptop-dock unit. This is
essentially a USB hub and display. The display is connected by
outputting from the phone's HDMI port. The rest of the input/output
device (keyboard and trackpad) are seen as USB connected devices and
interfaced via the phone's USB port (Atrix supports USB host mode).

Essentially, this laptop dock is what people are talking about except
for a generic host instead of for a phone. We would want to expose the
HDMI input generically and probably with an additional VGA input. Of
course there are also VGA-HDMI converters. Anyone wanna ring up
Motorola to see if they're interesting in adapting the Atrix
laptop-dock technology? 

As someone who's done video for 20 years, I can tell you, Jake: 

It ain't that easy.

The interface on the Atrix is purpose-built, and it's almost certainly
just a DVI/HDMI digital interface to a panel that expects that.

What's necessary for a standalone KVM of the sort we're talking about
is what the video people call a "genlock" circuit -- most machines that
need this at all have analog VGA out, and you have to have a chip that
can lock up to it, and extract the video from that analog signal cleanly.

This is, to quote the Jargon file, decidedly non-trivial to do well.

That's the reason why a single port unit, not on sale, is generally around
$400.  If it was DVI/HDMI *only*, it could be substantially cheaper, but
I've never seen one that was.

- jra
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]