From: David Brownell <[EMAIL PROTECTED]>
To: "Steve Calfee" <[EMAIL PROTECTED]>
CC: linux-usb-devel@lists.sourceforge.net
Subject: Re: [linux-usb-devel] Re: Question about OTG operations
Date: Tue, 28 Feb 2006 22:46:42 -0800
On Tuesday 28 February 2006 10:20 pm, Steve Calfee wrote:
> So for instance if you have a battery powered PC and wish to connect it
to a
> powered printer or a display device it would be nice if the A connector
goes
> into the "peripheral" and the b into the "computer" that way the
computer
> would get power and the device could hand off the awesome responsibility
of
> knowing what to do to the computer.
That's a very interesting example ... though it'd work better with a
battery powered PDA/phone/etc so it could also draw enough power to
recharge its little battery!
But I'm not entirely sure I'd expect most users to get that "A-end of
cable goes into the printer" right. The best visual indicator is that
the inside of that connector is white, not black; it's pretty subtle.
As I said to Leo:
Yes, it is a huge drawback to the spec. Being host does not say you provide
power, being "A" connector does. How do you communicate the fact that your
handheld can use and get power from a device if it is plugged in properly.
I have seen more devices with both A and B connectors, but that do not have
an OTG connector. However, the A device is only guaranteed to supply 8ma, so
only a "system" involving both a battery powered "pc" and a powered device
could even handle the obvious power handling used in OTG. Probably having
both A and B connectors is a more sane and clear indication of power and
connections.
Regards, Steve
-------------------------------------------------------
This SF.Net email is sponsored by xPML, a groundbreaking scripting language
that extends applications into web and mobile media. Attend the live webcast
and join the prime developer group breaking into this new coding territory!
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
