Audio level is high only if yellow (video) connected

I find this strange.

I am trying to use RCA jack to feed just the audio to line in of another
unit. I find that the output continues to come on the device, not
redirected to the jack.

But if I just connect the yellow (video) jack also to the external device,
the audio output starts coming.

Also, when video is connected, the audio output functions as if line-out
i.e. gives sufficient signal level giving normal sound level on the
external device.

So, not sure whether the audio out level is decided automatically
depending on whether the yellow jack is connected or not - probably it
assumes otherwise that you are using a headphone (?).

If so, the behavior should be software controllable i.e. can I achieve
line-out like output without connecting the video out anywhere?

Mayuresh.

On Sun, Mar 25, 2012 at 11:34 AM, Mayuresh <mayuresh@acm.org> wrote:
> So, not sure whether the audio out level is decided automatically
> depending on whether the yellow jack is connected or not - probably it
> assumes otherwise that you are using a headphone (?).

Probably. Same behavior happens with headphones -- if you get a
headphone extension cord and plug it into N900, nothing happens until
you plug the other end of extension cord into actual headphones (or
any device).

On Mon, Mar 26, 2012 at 09:37:47AM -0500, Paul Hartman wrote:
> On Sun, Mar 25, 2012 at 11:34 AM, Mayuresh <mayuresh@acm.org> wrote:
> > So, not sure whether the audio out level is decided automatically
> > depending on whether the yellow jack is connected or not - probably it
> > assumes otherwise that you are using a headphone (?).
>
> Probably. Same behavior happens with headphones -- if you get a
> headphone extension cord and plug it into N900, nothing happens until
> you plug the other end of extension cord into actual headphones (or
> any device).

Ok, so there exists h/w capability to drive line out, which is limited by
software? (Or is this behavior hardwired?)

How to unleash it - how to make N900 drive line out for audio-only?

Mayuresh.