Serial converter / RS232 transceiver

Hey guys, we have a custom cable that runs between a Silvus radio and a Pixhawk PX4. We believe that the custom board is acting as a serial converter / RS232 transceiver - but are having issues and want to create a replacement … or if not possible, bypass it … so we can confirm if this part is the cause of our connection issues.

Does anyone know of a replacement part we could use?

The chip has the following written on it “SIPEX 3232EE 1837L H1N76” and I think its this one:

There are 9 wires used from the cable coming out of the silvus radio primary connector:

  • 4 are the 2 x ethernet pairs - these connect to the RJ45 connector in the fuselage, for connecting directly to the radio via ethernet. This has been tested and works.
  • 2 are power to the silvus radio - assume these are ok as the radio powers up and works
  • 3 go to the small circuit board (serial converter board) - white, light-grey, light-green
    • Grey = RS232 Rx
    • White =RS232 Tx
    • L/Green = Gnd

the other side of the circuit board has 4 x wires

  • 2 are power (brown & red)
    • Brown = Ground
    • Red = VCC
    • White = RS232 Tx
    • Yellow = RS232 Rx


Hi Steve,

While I don’t know how to bypass it I do believe we have the equivalent chip on a nice breakout board available here so a replacement may be easy enough to whip up:


Thanks Matt. Board ordered - I’ll let you know how it goes.