Hi Peter
If you want your device to be the host and also charge from a power source =
attached to the cable.... I think you must use a 36.5Kohm resistor.  I may =
be wrong as I have not tried this yet ( I plan to )  and my information cam=
e from Wikipedia.  http://en.wikipedia.org/wiki/USB_On-The-Go

I have not found a suitable cable.  The micro-connectors ( plug ) are about=
 $1 each from Mouser.
Farnell has a HRS (HIROSE) - ZX20-B-5S - MICRO USB TYPE B, PLUG   HRS (HIRO=
SE)
Order Code:  1425723    Manufacturer Part No: ZX20-B-5S
It is not ideal... it was the best I have found so far...

Maybe this ?
http://www.karlssonrobotics.com/shop/usb-microb-plug-breakout-board/?gclid=
=3DCKDl4NS5rLICFaleTAod9wcAbg
https://www.sparkfun.com/products/10031

Gus


> On Sep 10, 2012, at 5:07 PM, peter green wrote:
>=20
> I've been playing with a google nexus 7 tablet recently and have found=20
> that despite having a micro B connector (host mode capable devices=20
> should have a micro AB connector) it IS capabale of host mode.
>=20
> However I'd like to be able to charge it and connect it to a USB device=20
> at the same time. According to the USB battery charging specificiation=20
> this is signaled to the device by placing a 124K 1% resistor between the=
=20
> ID pin and ground. I want to test if the nexus 7 will respond correctly=20
> to this.
>=20
> So does anyone know of a UK source for cables with a micro B plug with=20
> all 5 pins connected to wires in the cable? (I don't care what is on the=
=20
> other end of the cable) I found a source in the US for micro B=20
> extensions with all 5 wires connected (=20
> http://www.usbfirewire.com/uextendmicrob.html ) but $7.95 for the cable=20
> plus $8.50 for delivery in 3-6 weeks delivery seems a bit steep and slow=
=20
> to me.
>=20
>=20
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