[mythtv-users] DirecTV (RS232-to-RJ11 cable) -- I think I figured out my problem!

Tue Jun 10 00:30:17 EDT 2003

Ok, here are my findings so far.

DB9F pin assignment is definitely as follows:
5 4 3 2 1
 9 8 7 6

RJ22 pin assignment seems to (definitely?) follow:  (when looking at the
bottom, pin-side)
Pin-1
Pin-2
Pin-3
Pin-4

Following the pin assignment, I've connected:
(RJ22-to-DB9F)
1 - to - 5  [ground]
2 - to - 2  [receive]
4 - to - 3  [transmit]

Here is what happens:

1)  If I DO NOT connect the RECEIVE line (2 - to - 2), I can transmit to the
receiver PERFECTLY.  The receive changes channels, etc, etc and works
perfectly fine.  Of course I still get "a Timeout" response from the receive
because the RxD line is not connected.  However it will still change
channels.

2)  If I DO NOT connect BOTH the RECEIVE and the GROUND line, whenever I
transmit to the receive it will change to WEIRD channels and do weird
things.

3)  If I connect ALL THE WIRES, as soon as I plug the cable into the
computer and the receive, my satellite receiver will turn itself on and off
constantly.

I believe my problem is DEFINITELY located in the receive line.

If I can transmit fine (with TxD and Gnd connected only), then I think its
safe to assume my RJ22 and DB9F pin assignments (and connections) are
definitely correct.  However once I hookup the RxD line, I immediately get
problems ranging from receiver self shutdown/reboot or I get "Timeout"'s
when I send

Also, I measured my cable and it's 50' (I thought it looked longer than
that).  So, if I can transmit fine then I'm thinking I have one of two
possible problems:

1)  The satellite receiver is not strong enough to send a signal back to the
computer over the 50' of cable.  Can I test for this any easy way?  It's
hard to rewire my cables espicially if I had to chop the length back down.

or

2)  The diagram is screwed up and I'm actually suppoed to connect RJ22 Pin 3
to DB9F Pin 2.

Has anybody else built a cable like this that can possibly help?

Ray, thank you so much for helping me.  If you have any other ideas please
let me know.  I know I'm very to getting this to work.

Thanks!

[entire original message thread follows]
> First, please do not apologize for "being long". Troubleshooting cabling
> problems is always a matter of detail, and I'd much prefer to wade through
> some irrelevancy than to hit "I think I got that part right" in the middle
> of a report. And in facf none of the detail you provide is irrelevant,
anyway.
>

Thank you very much.

> At 08:39 PM 6/9/2003 -0400, John Klimek wrote:
>
> >http://www.pcmx.net/dtvcon/ -- this is the diagram that I tried to
follow.
> >
> >If you turn the phone connector (RJ22) upside (so you can see the gold
> >pins), I ordered them like this (top to bottom):
> >
> >1 (white)
> >2 (white)
> >3 (red)
> >4 (black)
>
> In looking at the URL, I can't really see which way they expect you to
> orient the RJ22 connector. Were I to guess, I'd make the same guess you
did
> ... but that still eaves it a guess, albeit a shared one.
>
> >Then, I cut a 75' (I think its 75', it appears longer than 50')  RJ11
cable
> >just to make my RJ22 cable longer.  Now, I connected these two cables
like
> >this:
> >
> >RJ22 --> RJ11
> >1 - (white) --> Green
> >2 - (red) --> Red
> >3 - Not used
> >4 - (black) --> Black
>
> Note that between these two descriptions, the location of the (red) wire
> moved from position 3 to position 2. Is this just a typo or does it
reflect
> a wiring error?
>
> If it is a wiring error ... as I read the wiring diagram at te URL you
> reference, this is the pin for RX (that is, the line the PC receives data
> on). Miswiring it would cause replies from the DirecTV device not to reach
> the PC, no matter how you wired the DE9 end.
>
>
> >Now, I cut an older cable that was used to connected an external modem to
a
> >desktop.  One end was DB25M and the other was DB9F.  I cut off the 9-pin
> >female connector.  It has 9 pins which are holes (I'm assuming this means
> >DB9F).
> >
> >Following the diagram, I connected as follows:
> >
> >RJ11 --> DB9F
> >1 - (white) --> 5 (Brown)
> >2 - (red) --> 2 (Red)
> >4 - (black) --> 3 (Orange)
>
> Another notation problem. Pin 1 on the RJ11 (above) was Green, not
(white).
> This time, though, I assume you are just still using the RJ22 color codes,
> not making a wiring error.
>
>
> >I used a multimeter (to check continuity) to check which hole on the DB9F
> >connector went to which colored wire.
> >
> >Now, before I added my "extension" (RJ22 --> RJ11), I used these hole
(pin?)
> >assignments for the DB9F connector:
> >
> >5 4 3 2 1
> >  9 8 7 6
>
> There are pins inside the holes, so I still call them pinouts. If you are
> viewing the connector from the "outside", this one is the right pinout set
> for a female connector.
>
> >The cable transmited, but DTVCON always gave a "Timeout" error when
waiting
> >for a response.
> >
> >Now, I tried reversing my DB9F hole assignments:
> >
> >1 2 3 4 5
> >  6 7 8 9
> >
> >The cable transmits, but again recevies a "Timeout" from DTVCON.
> >
> >My "reversed" hole assignments I think I have confused with a DB9M
> >connector.
>
> Me too.
>
>
> >Sorry for this being so long but I'm trying to be as through as possible
so
> >you could help me =)
> >
> >Thank you so much.
> [old stuff deleted]
>
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