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

[John Klimek]

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)

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

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)

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

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.


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.


----- Original Message ----- 
From: "Ray Olszewski" <ray at comarre.com>
To: "Discussion about mythtv" <mythtv-users at snowman.net>
Sent: Monday, June 09, 2003 8:06 PM
Subject: Re: [mythtv-users] DirecTV (RS232-to-RJ11 cable) -- I think I
figured out my problem!


> At 04:50 PM 6/9/2003 -0400, John Klimek wrote:
> >I built myself a DB9-to-RJ11 cable and have been having some problems.
> >
> >On the BACK of my DB9 connector, it appears to last the pin numbers as
> >follows:
> >
> >5 4 3 2 1
> >  9 8 7 6
> >
> >However, when I searched for RS232 pin assignment, I found the following:
> >
> >1 2 3 4 5
> >  6 7 8 9
>
> There is no one correct answer, since male and female connectors are
mirror
> images (and of course, the wiring side of a DE-9 is the mirror image of
the
> pin side ... I don't know which of these you are calling the "BACK" of the
> connector or which side you are describing the pinouts with respect to).
> This URL -- http://www.rhinorobotics.com/stwire9-25.html -- gives both
sets
> of pinouts ... viewed, as is so customary that they don't bother to say
it,
> from the pinout side, NOT the wiring side, of the connector.
>
> Assuming a standard serial port at the PC end, it requires a female
> connector on the cable, so the correct pinouts are the first of the two
you
> list above.
>
> >However, my cable SOMEWHAT worked.  It was able to change channels, but
it
> >didn't receive a "Success" signal after sending the command.
>
> One interpretation of this is that you have TX wired correctly but not RX.
> Since TX is pin 3, it goes to the same pin with either of your pinout
> choices, but RX, pin 2, changes. In this case, you would also have SG
> miswired ... I've seen odder things than a serial cable without a ground
> return working, but that might cause some, as you say, "very weird
results"
> ... especially since I don't recall what handshaking line, if any, this
> cable uses.
>
>
> >I rewired my cable (using incorrect (?)) using a 50" (might be longer)
> >cable, and I'm getting very weird results:
>
> I assume you mean to write 50' (50 feet), not 50" (50 inches).
>
> 50 feet is long, but not unreasonably long for a standard serial cable.
> Back in the days when I used a lot of serial connections, I used cables up
> to 100 feet routinely (to connect serial terminals to multiuser PCs ... I
> *said* it as a long time ago). Of course, what is generally true may not
be
> true in a specific instance, so you might want to check on whether the
> DirecTV device has some wimpier serial implementation than the standard.
>
> >1)  When plugged into one computer, the satellite receiver kept turning
on
> >and off every few seconds.
> >2)  When plugged into the other (Win XP, using DTVCON), it somewhat
worked.
> >It would change channels, but sometimes it would change to the wrong
channel
> >(is my cable too long?)  and I was still unable to receiver a "Success"
> >response from the satellite.  I got a ton of Buffer errors.
> >
> >Sorry for the long post.
> >
> >I'm wondering if a 50" or 75" cable is too long for the cable and is my
> >wiring incorrect?
>
> Probably not too long. But if you are worried about this, test with a
short
> cable (cables aren't that hard to make if you know how, as you clearly
do).
>
> You don't actually *say* how you wired the cable, so I can't say whether
> what you did is right.
>
> >I'm using a continuity tester to make sure the signal is passing through
the
> >cable, so I know that isn't the problem.
> >
> >Thanks for any help.  After I get my cable working complete, I'm going to
> >write a very detailed HOW-TO with pictures to help out anybody else who
> >might be having problems.
>
> If you are the guy who posted on this a week or so ago, I **think** I
> recall two things:
>
> 1. The DirecTV end was an RJ22, not an RJ11.
>
> 2. The Web sites about wiring this cable have at least 2, maybe 3,
> suggested wirings. If you have RX, TX, and SG all wired correctly, but
> whatever handshaking line the DirecTV device expects to use is wrong, that
> could cause intermittent errors.
>
> (If you post again, please include a URL for the cable-wiring diagram you
> actually followed.)
>
>
>
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