From: Joseph Jones <joe_at_bumpycarrot.cjb.net>
Date: Tue, 10 Feb 2004 22:28:49 +0000

[IDC]Dragon wrote:
>>Right, so it's kinda... half-duplex without modding the box?
>
>
> Correct.
>
>
>>So... some kind of two-way communication is possible without internal
>>modding, though it may not be overly fast?
>
>
> Yes, I use this e.g. for my Alpine CD changer emulation, to hookup to a car
> stereo. It doesn't require much speed.
>
> The max. baudrate on the RX (remote) pin is 345600 Baud for a recorder,
> Clk/32. The transmit would have to be done by bitbanging, which can also be quite
> fast. We do similar for the LCD and get >800kHz.
>
> It can be envisioned to tie multiple boxes together and form a kind of
> network with it, collision detection like for ethernet.
>
> Jörg
>
>
>
>

So fairly fast communication could be possible, it just wouldn't be any
kind of existing protocol for the low-level stuff.

Is the RX pin the 4th pole on the headphone socket that the in-line
remote hooks up to? So there'd be two physical connections for two-way
communication?

That seems reasonable :) In fact, for an Mp3 player, it's options seem
quite wide.

I think I'm gonna have to pick up a C book after this week's over (ICT
coursework implementation and the start of testing to be in on Thursday,
or my head). If I'm hoping to be getting to grips with networking
anytime soon, I'll have to study double-time :)

I don't hold up much hope in myself, but a little pipedream never hurt
anyone :)

It's interesting seeing just what is possible with the hardware to hand.
I mean, we've already got faux-greyscale movies with sound, and it was
no way designed for that :) I'd say Rockbox adds a good ~£100 to the
value of a JBR :)

Joe
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Received on 2004-02-10