[mythtv-users] Nvidia ION unreliable HDHR Prime at gigabit speeds

[Mike Perkins]

On 28/02/16 03:14, Gary Buhrmaster wrote:
> On Sun, Feb 28, 2016 at 2:23 AM, Will Dormann <wdormann at gmail.com> wrote:
> ....
>> I see now that my cable box has what appears to be a 3.5" jack called
>> "IR Remote Input".   Which I would assume the MythTV box can perhaps
>> control w/o IR anywhere in the chain, right?  i.e., serial to serial.
>
> Well, "simulated" IR blaster to "simulated" IR receiver (with
> no actual IR (except inside the IC) involved).  You still need
> a "blaster" which accepts a plug for the emitter itself, and then
> plug the output into the IR in port.  Sometimes you can use
> a serial output port of your PC, and sometimes you want a
> "real" blaster to meet the tolerances of the receiver (I had
> used both an iguanaIR and the commandIR for my "blaster"
> in a previous life).
>
>> Or is the opto-isolator used because the IR Input port isn't designed to
>> be electrically connected to another system, due to ground loops or
>> whatnot?
>
> Right, potential ground (loop) issues.  While "usually" it
> will work sharing ground, I am a bit on the paranoid side,
> so designed a circuit which shared nothing.  Many others
> have done equivalent solutions (what I did is not special).
>
> There are a lot of solutions out there (if you look around
> for (old school) TiVo to DTA/STB direct connect cables
> in the usual places).
>
>>   Either way, do you have any links to your contribution to the
>> wiki?
>
> For the lirc channel changer script, I submitted/used this:
> https://www.mythtv.org/wiki/LircChannelChanger
>
> For the opto-isolator, I documented this at:
> https://github.com/garybuhrmaster/misc/tree/master/IR_Blaster_to_Comcast_DTA_direct_connect_cable
> (I did not add it to the mythtv wiki since I figured it was
> too specialized).
>
> In any case, as long as firewire works for you, I would
> not touch it.  Just keep the idea of alternatives in your
> toolbox for future use.
>
The point is not that firewire works for him, but that if there is a reasonable alternative he can 
remove the FW card from his box and substitute an Ethernet card instead, thus resolving his 
networking problem.

-- 

Mike Perkins