[mythtv-users] directly driving an STB via a "remote extender" input

[Mike Perkins]

On 11/03/12 20:10, Gary Buhrmaster wrote:
> On Sun, Mar 11, 2012 at 11:09, Brian J. Murrell<brian at interlinx.bc.ca>  wrote:
> .....
>> I wonder if anyone has any experience with driving that "IR in" port
>> directly.
>
> Over the years there have numerous discussion of such solutions,
> including for Tivo's, STBs, and when Comcast rolled out their DTAs.
> The specific wiring diagrams were not always consistent due to
> there being no standard (which of the tip, ring, ground is +5,
> ground, sensor out).  Someone posted on the web a diagram for
> a Tivo/Comcast solution: http://grayeng.net/TiVotoComcast.htm
> and references an eBay link for one of the various versions being
> sold (on eBay).  There are also some posts in the archives of
> this list, along with various discussions on the Tivo lists.
>
It sounds like a good idea, but in almost all cases you will need to provide DC 
isolation between the two boxes, because of the way modern power supplies 
function and the possibility of earth loops.

The ideal way to do this is with an opto-isolator, which is... a LED and an 
opto-receiver placed face-to-face... which is exactly what you started with in 
the first place. The only thing you might gain is that the components are 
shielded from light interference. What you might lose is having to solder the 
thing together, unless you're a hardware geek.

-- 

Mike Perkins