[mythtv-users] Serial control of D11-500, some data getting to receiver

Brad DerManouelian myth at dermanouelian.com
Mon Jan 29 16:38:47 UTC 2007

On Jan 29, 2007, at 8:12 AM, Jeff Simpson wrote:

> On 1/18/07, chris at theromeos.us <chris at theromeos.us> wrote:
>> I'm trying to use the directv.pl script modified by Jeff Simpson  
>> to change
>> channels on my D11-500 DirecTV Receiver.  I'm using a Sabrent CUS6M
>> USB->Serial Converter.  It seems to be the longer version of the  
>> listed on the Wiki entry for controlling the STB.
>> I have two different null modem cable combinations that I'm  
>> working with.
>> I've enabled hardware flow control using stty for my com port.
>> When I execute the script and use on or off the receiver receives the
>> command and acts upon it, but then returns a 0xE0 for each  
>> response (the
>> response is supposed to be a 0xF0).  The receiver will shut on or  
>> off, but
>> then the script loops through the remaining retries and continues  
>> to say
>> TimeOut.
>> When I try to change channels with the script, the first number on  
>> the
>> channel gets to the receiver and displays on the screen as if it  
>> was typed
>> in by the remote, but then the script displays a Time Out error and
>> retries the first character again.
>> Is anyone aware of any recent changes in the protocol in use by  
>> the STB,
>> or have any other ideas for what could be causing this behavior?
> That's a new one for me. Typically if it doesn't just magically work
> when it's all plugged in and set up, it's a problem with the cable.
> The fact that you are able to get the first button press to work fine
> seems to say that the cable is fine, or at least mostly so.
> What options have you tried tweaking as far as baud rate, parity, flow
> control, etc? I've heard mixed results between 9600 and 115200 bps,
> and various flow control options.
> You may be able to modify the script slightly to accept E0 as a
> success and have it continue on. If it is in fact working properly,
> that is. You may also be able to tweak the delay times between key
> presses to see if that helps you.
>  - Jeff

I mentioned in another thread (and added a note to the wiki) that my  
baud rate changed from 115200 to 9600. I had this confirmed by  
another user who mailed me off-list. My channel changing was failing  
because of this but it's possible that some codes are being sent and  
interpreted incorrectly because of it.

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