MythTV Satellite Howto

These will hopefully assist others in getting their directv satellite reciever working with MythTV. The availible information when I set mine up was somewhat erratic. Hopefully this will save you some pain and patience.

The first thing you need to do is build a cable. My RCA 420RE reciever has a "Low Speed Data" port that is a RJ-22 port. (Normal Phone cords are RJ-11). You need to go shopping. Go to radio shack and get a rj-22 cable if you can find one, I believe phone handsets use RJ-22. If not, you can make due with a RJ-11 cord. While you're there, pick up a DB-9 female connector and a hood to make life easier. I prefer the solder type connectors. If you work in networks like me, you may have a RJ-45 to DB-9 universal connector that you just have to hook the pins into the right holes. This is the easiest. MAKE SURE THE cable you buy/find has 4 wires, and NOT JUST 2!!!!! If you could only find a RJ-11 cord, you can do what I did. Either use a pair of pliers and a bench grinder or a dremel tool to grind down the sides of the RJ-11 connector on one end of the cable. I did this, and just used a piece of tape to secure the caple in the port, since the lock tab doesn't work. You'll also need to make the index tab on the RJ-11 connector narrower. Look at the hole and figure it out.

Onto the pinouts!
Note that the cords cross over, pin 1 on one end is black and pin 1 on the other end is yellow. This affects how you wire the pins, so it's important.
DB9 Signal RJ-11
Pin 5 Ground Pin 1
Pin 2 RX Pin 2
Pin 3 TX Pin 4
Pins of the RJ-11: Look at For a nice picture. Otherwise, pick up the cable and look at the end. Hold the cable with the end away from you, so that the cable runs toward you. With the gold contacts facing you, upward. The wire on the left side is Pin 1. The wire on the right is pin 4. 2 is obviously next to 1. Now, take a look at the other end. Note that the wires change pins. If you're going to solder your cable together, go ahead and lop off one end. Now write down which color wires are which pin to the remaining end. Solder or build your cable to the pinouts in the table.

Go ahead and plug the cable into your reciever. If you have a windows box with an availible serial port, this process is a bit easier, as you can download some shareware software to test your cable with. Go visit There pull down the DirecTV Control Software to your windows box. Don't forget to plug in the DB9 to your windows machine. Now see if you can control the reciever. The easiest test is ON and OFF. If it does't work, go right click on the app in the title bar. Select the newer protocol. Now try it out. RCA changed their serial protocol a bit, just to annoy people. Now have fun playing with it. If it doesn't work at all, make sure you selected the right ports, and go double check your pin outs. Preferably with a multi-meter. You'll need a small wire to get contact with the gold leads in the RJ-11 connector.

Now, if you used the old protocol with the windows software, you can use the script. If you used the new protocol, you can probably use the script. The scripts are availible at Download the right script and edit it to select the proper serial port for your myth box. Don't forget to plug the DB9 into your myth box. On mine, I used /dev/ttyS0. Next, try the script out. They won't power on and off the reciever, since Mythtv doesn't do that. All they'll do is select channels. chmod 755 the script and try it './script 100' should set the reciever to channel 100. Mine set the channel to 1, when I used the script, but the script worked just fine. Here's a copy of and

Finally, go setup MythTV to use the satellite. When you add it, just point mythtv to the correct script for the channel changing.

Now go have fun.

Disclaimer: It's not my fault if you hurt yourself, set your pet on fire, or have problems getting dates due to the information provided on this page. Use appropriate safety measures while playing with power tools. Kids, ask your parents for help!