In article , Francis C. wrote:
William Sommerwerck wrote:

I believe the resistor is needed to "clue" the power supply that
something that "wants" to be charged is connected.

I'm confused because I just tested a "normal" cable and this was
my observation:

Motorola RAZR V3 connected to wall-wart USB charger -- fail
Motorola RAZR V3 connected to automotive USB charger -- fail
Motorola RAZR V3 connected directly to Linux PC -- charged!

The weird thing is that I used the same cable for all 3 tests!

USB has power control from the host. The Linux system is going to
interrogate the phone and set up the internal hub/controller to whatever
power level the phone wants.

A brainless charger can't do that negotiation. So there has to be a
setup where the phone will sense the resistor and see that it's hooked
up to a brainless charger and just go ahead and charge.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)