Obtain 5foot CAT5 wire.
Strip back 3/4" of the outer jacket from one end of the CAT5 wire.
Strip back 18" of the outer jacket from the other end of the CAT5 wire. Note: Using a box cutter, cut around the outer jacket of the CAT5 at 18" from the RJ45 end.
Next, using diagonal cutter, cut the outer jack toward the RJ45 end about 2".
Pull out the brown and white&brown pair from the 18" end so the outer jacket will easily slide off
click to enlarge
On both ends, cut and dispose of brown, white&brown, white&blue wires.
On the RJ45 end (18" end), Trim the orange, white&orange and blue wires back to 5/8" from end for RJ45 connector.
Fold back the 18" long green and white&green pair. Place a 1" long heat shrink over the CAT5 and green pair. -- don't heat the shrink yet. Note: See photos below of heat shrinked end.
|Insert 3 conductors + folded back end of green and green+white wire into RJ45 and crimp such that the blue, orange, white&orange wires are as shown to the right and down below.|
|Cook the heat shrink.See photo
click to enlarge
Strip the ends of each wire, orange, white&orange, blue, green, white&green to 1/4".
Twist white&green and white&orange wires together. These are the ground wires. Tin, trim (to remove spurious untwisted bits) and attach the twisted pair to DE-9 as per drawing.
Tin, trim and attach green, blue, orange wires to DE-9 as per the drawing.
Solder 17" long green wire to center conductor of earphone plug. Solder white&green wire to ground of earphone plug.
Note that reversing these two wires on the earphone jack is the number one cause for failure of this cable!
Note: MIC is the same as TxData for our purposes. Speaker jack center conductor becomes RxData. The ground from the speaker jack must be connected to the Microphone Ground and both are soldered to pin 6 on the DE-9 connector.