[mythtv-users] HD PVR and IR transmitter for channel change (why)

Brian Wood beww at beww.org
Wed Dec 15 15:59:31 UTC 2010

On Wednesday, December 15, 2010 08:29:34 am Dave Richardson wrote:
>  Sorry if this is remedial, the wiki does not appear to address the
>  topic...
>  http://www.mythtv.org/wiki/HDPVR
>  If the setup for an HD PVR from cable STB is
>  STB --> [composite] --> HD PVR --> [USB] --> Myth BE
>  Then the wiki appears to jump straight to a conclusion that the IR
>  Transmitter channel change wiring and setup is
>  HD PVR --> [ir emitter] --> STB
>  with a lot of instruction about how to ensure modules/kernel and
> myth setup are done.
>  My QUESTION: there seems to be a leap or assumption made that this
> is the best/correct IR transmitter setup to channel change on the
> STB.
>  Can someone please elaborate on this?  Are there other options or at
>  least reasons why this approach is favored?  My gap in understanding
> is that this is not similar to how IR transmitting is done when
> capturing from STB -> PVR 550/150 or other setups.  Why is the HD
> PVR IR Transmitter favored over IR transmitting from the BE?

I don't know, but some possibilities are:

The placement of the HD-PVR may be different from the location of the BE, 
up to the 15 foot limit for a USB cable anyway.

In my case the HD-PVR is on the other side of a wall from the BE 
machine, which is in the garage.

Obviously you can run a wire from the BE to an IR emitter, and you can 
probably run it farther than the limit for USB, but using the HD-PVR's 
emitter eliminates one cable.

The HD-PVR emitter may have more IR power than a serial-port driven 
emitter, since it has it's own power source.

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