Comms lead with usb end

Wiring best practices and loom building technique
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welshpug
Posts: 130
Joined: Tue Sep 06, 2011 4:53 am
ECU Model: S40 Pro

Comms lead with usb end

Post by welshpug »

any reason why I can't just make an USB to 15 pin serial plug instead of having to use an usb to 9 pin lead then 9 to 15 lead?

can't see any!

would save me quite a bit as I could probably make up a comms lead for a fiver!


intrigued also to know what exactly a pot box entails further than 3 buttons whilst I'm at it, not sure what exactly the knobs do (I know what they do in the software!!)
stevieturbo
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ECU Model: No ECU
Location: Norn Iron

Re: Comms lead with usb end

Post by stevieturbo »

welshpug wrote:any reason why I can't just make an USB to 15 pin serial plug instead of having to use an usb to 9 pin lead then 9 to 15 lead?

can't see any!

would save me quite a bit as I could probably make up a comms lead for a fiver!


intrigued also to know what exactly a pot box entails further than 3 buttons whilst I'm at it, not sure what exactly the knobs do (I know what they do in the software!!)
Well apart from the fact USB communications and serial are totally different. Yea you could wire it up whatever way you want.

And the buttons do exactly the same thing in the software, as they do in your hand. Obviously in your hand it's faster and easier. And search, there are wiring schematics already.
welshpug
Posts: 130
Joined: Tue Sep 06, 2011 4:53 am
ECU Model: S40 Pro

Re: Comms lead with usb end

Post by welshpug »

so what makes having an extra 9 pin plug with only 5 wires in it being used between an USB and the 15 pin plug on the ecu work then? what am I missing :lol:


thanks for the pointer for the info on the pot box, took a while to find :D
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ignitionautosport
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ECU Model: S80 Pro
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Re: Comms lead with usb end

Post by ignitionautosport »

There is a chip that converts the USB signal to an acceptable RS232 signal.
RS232 has no protocol standard, however USB does (and are significantly different).
The chip in the converter requires a driver, as USB protocol is done at the software level (or something like that) - I can't find the document I found earlier today that outlined it now.

There is enough going on that you can't just run wires between a USB and 15way connector. It may however be possible to swap out a 9-way for a 15way as the physical size is still a DB9.
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welshpug
Posts: 130
Joined: Tue Sep 06, 2011 4:53 am
ECU Model: S40 Pro

Re: Comms lead with usb end

Post by welshpug »

gotcha!

cheers :)
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