[mythtv-users] DirecTV -- Satellite Serial Port -- How can I build the cable?

[Ray Olszewski]

At 03:25 PM 6/3/2003 -0400, John Klimek wrote:
>This is my first time posting to this mailing list...  MythTV looks simply
>INCREDIBLE and I'm very much looking forward to using it.
>
>At first, I thought this wasn't possible... but you can control your satellite
>receiver (channels) from your PC by using a serial cable?

Depends on the receiver. Some yes, some no. A data port is a necessary 
condition, but not a sufficient one.

>My receiver (an RCA, I forget model) does indeed have a "low speed data 
>port" so
>all I need to know is how to build the actual cable.

I doubt it. Unless, that is, you already know know the serial port settings 
(baud rate, stop bits, parity ... the usual stuff) and the actual codes 
that need to be transmitted.

In any case, you'll need to find out the model number. Also tell us what 
the port looks like (standard 9-pin serial? RJ-45 (like an Ethernet port)? 
RJ-11 (like a phone line)? something else?)

One long shot -- a crude Web search turned up a Snapstream package for 
controlling RCA DirecTv satellite receivers, specifically "RCA Model 
#4XXXX". It includes the right kind of cable to attach to an RJ-11 port on 
the RCA end. You might see f that is what you need. Reference is
         http://shop.store.yahoo.com/snapstreammedia/rcadirbun.html

Also see this site:

         http://www.pcmx.net/dtvcon/

If they don't help ...

If it is a 9-pin port, the only real question is whether it is wired DTE or 
DCE. I've never seen this answered for ANY cable box, so I suppose you'll 
have to find out by testing. Just search Google for serial-port pinouts to 
find the 2 relevant wiring diagrams.

If it is an RJ-45 ... I know of no standard pin assignment for them. If you 
can't locate documentation for the box, experimenting to get the pinouts 
will be a challenge.

If it's something else ... who knows? (Except for old DB-25s, and I doubt 
it is that.)

>I did try searching the mailing list archives, but I couldn't really find
>anything.

Provide all the detail you can. Including if there is any information about 
using teh box with a TiVo or any other commercial product ... what does 
your cable company *say* the port is for?

Figuring this stuff out is a bit like a scavanger hunt. Finding actual docs 
for the box is improbable, so you need to piece the relevant details 
together. You won't find a cookbook for this anywhere.