[mythtv-users] determining power state of firewire cable box

Preston Crow pc-mythtv08a at crowcastle.net
Sat Jun 13 20:59:10 UTC 2009

On Tue, 2008-12-30 at 12:16 -0800, Sam Logen wrote:
> I've got a motorola DCH-3200 attached to my mythtv setup via a
> firewire cable.

I know that this is an old thread, but I just got the same box, and was
dealing with some of the same problems.

>   The way I've set up my boot process, it primes the firewire port
> before mythtv starts up.

I haven't figured out exactly how best to do that.  I wish that Myth
would do that automatically as part of the firewire tuning process.

> I've downloaded and compiled the latest "6200ch" from svn.  I noticed
> that this script has the capacity to toggle the power state of the
> cable box.  So I modified its source to include my box's vendorid,
> then compiled it.  Toggling the power of the cable box with "-w"
> works, but all it does is toggle.

Yup.  But then I realized that the current trunk version of Myth handles
tuning of firewire without using an external tuner.  In fact, I couldn't
get it working with 6200ch, but letting Myth change the channels works.
It will even turn on the box if it's off.

> Is there a simple way to query the power state of the cable box via
> the firewire connection, so that if it returns a value meaning the box
> is off, it can power it on with the 6200ch "-w" switch?

Yes, there is.  I took the code from Myth's firewire tuning code, and
added it to 6200ch, creating a '-q' option to query the power state.
That made it easy to create a channel change script that powers the box
on if needed (which I needed to record with the PVR-250 on 5C-encrypted

I can post my changes if anyone wants them.  I'm looking for the best
way to get them incorporated into the subversion code base.

On a related note, I have some follow-up questions:

Is there any command to query the currently tuned channel?

When watching shows over firewire, I get a bit of a stutter.  I think
this is coming from the cable box (skipping back produces the same
stutter, and there are no digital artifacts).  Has anyone else seen

With the DCH-3200, I'm only able to get it to work in broadcast mode at
100Mbps.  Does that really matter?  Has anyone had success with other
modes?  What is the advantage of point-to-point mode?

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