Hi All,

Just bought my new n900 and absolutely loving it!!! However this is one small issues I want to get to the bottom of.

My n900 came with a Europe style mains plug which is no good for me here in APAC. So I wanted to use my iPhones Mains USB adapter/charger which worked for my android phones as well. But it does not work for the n900. I use the orignal USB a to micro USB B cable that came with phone. If I plug into PC the n900 detects the connection and charges. But if I plug into the iPhone adapter/charger or a usb cigarette charger in my car, they both are not detect by n900. The n900 will do nothing.

So I assume there is something with the pinning of the micro USB B connection. In particularly pin 4.

Does anyone know why this problem is? And does anyone have any kind of pinout schematic specific the nokia mirco usb cable or the mains charger that is AC-10X part number?

Thanks in advance,

Paul.

Search within the forum. n900 requires data contacts (I may be wrong) to be shorted to recognize charger. So pinning is standard, but it is not enough to just provide power, as all chargers usually do.

new micro usb charger standard say that data lines ( pin 2 & 3 ) must be shorted for detecting charger. this is imposed in 2006 by chinese government and adopted now wide on the industry. and is part of the usb2.0 standard.
n900 charging circuits are smart enough to detect computer wich can provide 500 mA or high power charger up to 1.8 A ( data lines shorted )
google is your friend .

No note quite shorted - though shorting works - the I think the spec is to have either a resistor between data pins or from one to V- and the other to V+.

Still, I've gone round my battery packs, 12v-usb adaptors and hack circuits and shorted D- and D+ and it works a treat.

definitive explanation
you can put between data lines an resistor from 0 ( short ) up to 200 ohm ( max value according standard )

Thanks everyone!!! That's awesome! Thanks for your quick responses and yeah, I guess I should have checked usb.org. My bad.

Excellent Work,
Now why does the iphone chargers not support this standard?

Hi,

Yeah, I have the same problem. Neither my generic mains-to-USB adapter, my Garmin mains-to-USB adapter nor my iPod-mains-to-USB adapter will charge my N900.

What happened to standards? I thought 5V DC out was sufficient, clearly not! The N900 knows if I plug in the Nokia mains lead as when I unplug the microUSB end it tells me to save the planet and unplug the mains charger. And the Nokia USB lead will only work if plugged into a computer USB port, so it knows where I'm plugging it.

So, is it possible to get a Mains-USB-Adapter that will work with all USB chargeable devices? I'd prefer to take just the one mains-to-USB adapter on holiday with me.

Thanks in advance.

@will177
All you need to do is make yourself a microusb nubbin that shorts the data lines. Buy a microusb socket and a plug, solder the voltage lines across, the data lines on the socket together and epoxy the whole thing to death once it works.
That way you can keep your non-standard charger for old devices, and use the adapter for new standards-compliant devices.

Hello!

You can get charging working with higher current if you connect 200ohm resistor between USB connector datalines.
Best Regards: Eero
- Happy N900 user