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pyro asked

VE Direct Extension Cable Connector Gender

Hi,

I am having trouble getting a VE Direct to USB cable work with a 5 meter VE extension cable I purchased. First I was surprised to find that the extension cable does not mate up with USB converter because it is male to male.

BMV-712 Female Connector --> Male VE Direct Extension to Male --- NOT OK---> Male USB VE direct converter

The extension is male to male while the USB is also male. I cannot find any Victron products that allow this. I now realize some people recommend a USB extension cable, but that is to late as this cable is already routed and sealed into the boat bulkheads.

I have attempted to make a gender changer and I am fairly confident I have the pin order correct. See pic as example. But my laptop does not see the BMV-712. It does see the FTDI device.

Is the cable just too long? Perhaps it doesn't like being run across a few feet of +12V battery cable? I don't really have any other choice.

I am hesitant to reverse order of the connector which would switch +5V and GND. Not sure if the devices can handle that if it's incorrect.


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3 Answers
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pyro answered ·

Confirmed that swapping pins 2 and 3 fixed issue. I now have communication. I built a male to male cable that does the conversion. Was pretty difficult given the tiny size of the connector.


Def easier to use the USB extension cable if I were to do this again.

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mvader (Victron Energy) answered ·

Hi. Just as context: we don’t sell extension cables (male/female) for a reason: you can’t extend vedirect communication beyond the max length vedirect cable we sell. Without running into communication issues that is.


but that doesnt help for your use case, the usb-vedirect-cable.


extending the vedirect usb cable is most commonly done by using a good quality usb extension cable.


the extension you’re making would need to be a straight pin to pin connection. Impossible to do wrong, I’d think.

So if it doesnt work, I’d expect it to be becuase its too long, or not twisted, or something like that: signal to noise ratio.

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pyro answered ·

I think I figured it out. Based on the distances, I assumed this was RS-422 (differential RS232 used for noise immunity). In fact it does seem that's it's just basic RS-232 which needs the classic TX-RX swap. The USB side is technically a crossover cable as it expects to cross TX-RX of a Victron device. Then the VE-direct cable is also a crossover cables. So two crossover cables in series are canceling each other out and putting TX to TX.

Going to try to make a TX-RX swap on pins 2 & 3 and see if I get communication. Will report back.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ commented ·

Good one!

Wrt the level, its not even rs232 voltage levels, its a much weaker signal (ttl)

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Related Resources

VE.Direct protocol FAQ