is it possible to spilt a usb for hu?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121839
Printed Date: May 12, 2025 at 8:55 PM

Topic: is it possible to spilt a usb for hu?

Posted By: juice steez
Subject: is it possible to spilt a usb for hu?
Date Posted: May 14, 2010 at 5:30 PM

So my HU (JVC KD-AVX77) has a single USB (F) that I use for my iPod but I would like to wire it up to a switch (maybe a DPDT DPCO) so I can have another open port so I can use to switch to and from my thumb drive. Now this is a little above my paygrade and I'm stuck, I'm not sure how to wire this up. The USB uses 4 wires Red (PWR) Black (GRND) Green (Data+) White (Data-), but I don't know what switch I need or if I also need a diode. Idealy I would like to plug in a USB (M)to the existing JVC USB(F)and have that (M) USB go to a switch that contros two USB (F) where I can plug in my iPod and leave one open so I can flip the switch and plug in a USB thumb drive.

I have a DPDT Switch that I picked up but not sure if it will work
3A 125VAC
1.5A 250VAC T85
posted_image

Replies:

Posted By: oldspark
Date Posted: May 14, 2010 at 7:58 PM

DPDT should work if switching power is sufficient - ie, the two outer pins in a standard USB.
But I think data lines can be left connected (especially if unpowered).

But I would NOT connect two powered sources (F) together!! Only an (F) to cards, sticks etc.

But I would recommend you get a 4-port USB hub instead. (Not that that normally allows source to source either...)

Posted By: juice steez
Date Posted: May 14, 2010 at 9:58 PM

USB Hubs (self powerd or otherwise) don't work on this HU, i have a solution for myself but I'm stuck on what diode to use and whitch way to point it

posted_image

Posted By: oldspark
Date Posted: May 14, 2010 at 10:31 PM

As I said, I'd do it the other way - switch the power, not the data. (But I've forgotten the USB spec - whether data is hi-impedance when unpowered or not in use).

And the diode should be where you have it (Diode?) with its line (Kathode) upwards to that +5V can go from the iPod (with a ~.2-.6V drop) to the VBus but the HU cannot power the iPod.

Posted By: juice steez
Date Posted: May 19, 2010 at 12:27 PM

Thanks, I will try it both ways and see witch works best.