I need to build a cable to go from my serial port (9 pin, DE9) to the low speed data port (4P4C telephone connector) on my DirecTv receiver. I have the serial port and the phone cable that I need to construct it all with.

I've searched the forums and the best reference I found was to check out http://www.dtvcontrol.com/index.aspx?content=cable
However, I do not understand exactly how to do it, and I want to be very clear so as not to damage my DirecTv receiver.

The telephone cable has 4 wires: black, red, green, and yellow. The serial port has 9 pins. I can interpret the the table from the above website in two ways:

Connect black phone wire to pin 5 on the serial port
Connect red phone wire to pin 2 on the serial port
Connect yellow phone wire to pin 3 on the serial port

or,

Connect yellow phone wire to pin 5 on the serial port
Connect green phone wire to pin 2 on the serial port
Connect black phone wire to pin 3 on the serial port

(phone wire being the 4P4C, and serial port being the female DE9)

In either interpretation, only 3 of the 4 phone wires are being used. In addition, I expected to have a ground wire connect to the metal casing of the serial port (isn't that standard?) - but I have no idea what wire to use for that.

Any help would be appreciated, especially a diagram!

Thanks and happy holidays!

the two ends of the phone handset cable you need touse are different. Take a look at the picture and wire up correct depending on which end of the cable you are using.


Pin 5 on a DB9 is ground

You only need 3 wires for RS232: rx,tx,gnd

Thanks for clarifying!
I'm sorry to sound so dense, but, is this correct then?

If using the side of phone line that goes (from top to bottom) black, red, green, yellow:
Black goes to pin 5
Red goes to pin 2
Yellow goes to pin 3

I assume then the black wire is the ground wire.