FTDI cable: 3.3v or 5v


I can see that 3DR sells 3.3v FTDI cables. But I was not able to confirm by searching this forum if 3.3v is the only option or if a  cable with TTL level of 5v will also work ?

I already have a 5V cable and I just don't want to try it and fry my module.



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  • Note that VCC is 5V, only the signal wires are 3.3V according to 3DR and the cable manufacturer's spec sheet. 

    3DR's page states: "Note: The TX/RX signals are 3.3volts, making it even more flexible, the power supply is 5volts (red wire)."


    Why do they state it is more flexible?  Will a 3.3V signal work with a 5V system?


    Also, if your board is using 5v signaling, I hope that won't harm the RS232/USB convertor chip inside the cable (which expects 3.3V).  took me awhile to realize FTDI is simply a company which makes the RS232/USB convertor chip...dumb idea whoever decided to refer to them as FTDI instead of RS232.

    • Hi Eric

      Just a quick question did the 5v signal cause any harm to the OSD ? I've just bought a FTDI breakout but see now that it's 5v logic .

  • Developer

    Either cable will work. The 3DR radio actually works for input power down to about 3v, and the serial interface is 5V tolerant.

  • Ok. I spent some time searching this forum but I did not really read the product page on the 3DR store. And it says:

    "Interface to the module is via standard 5V-tolerant TTL serial / FTDI USB serial."

    So why is a 3.3v cable sold with the module.


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