the 2mm nokia plug is..... nokia specific... didn't knew that nokia is the whole universe....
well fine, I wonder why I have other usb devices that charge their battery (a samsung ogg player for example) while still allowing me to access and store my music on them...
well that's the nokia design that is annoying... if they had made another design instead of [I]forcing[\I] users to buy their proprietary plug I think that it would have been [I]MORE[\I] convinient for the user...

if you have links to thoses schematics I would be greatfull... and again this is a choice made from nokia engineers... their are lot of devices that can charge through usb, or even power themself through usb (yes! yes! I assure you, their are even usb key that don't require an external power supply!)
JL

Well nokia is going in the direction of "one plug fits all" - http://gadgets.boingboing.net/2007/0...facturers.html.

I have the Nokia 6500 classic, which only has one connector - the micro-usb. Connecting the usb cable works fine for simultaneously charging + making the memory available to computer/sync.

Why this connector is not implemented in the newer models is strange though....

Well, perhaps I'm mistaken, so rather than risk putting my foot in my mouth, I'll ask you: Does your Samsung allow you to play music while it's connected to the computer for file transfer?

No. It's not Nokia's design, it's your design, the implications of which you don't seem to have fully considered. Nokia's design separates data and power ports, allowing you to power the device regardless of what data connections (in host or device mode) you might be using.

There are three issues here: Using a custom connector, hijacking a data connector standard to serve as a power connector, and combining power and data on one port. The topic of this post regards the third, but you're bringing up the first as though it is an inherent result of fixing the third. It'd be possible to use a different connector for power, and keep the proper separation of power and data. (Of course, there are no non-proprietary standards for connectors of equivalent size, but Nokia has published their standards for the 2mm interface; I don't know of any better power connectors anyway...)

And they don't force you to buy anything; it comes with an AC adapter, and if you need an adapter for any of USB, car, or AC, they're readily available from third parties. Forcing me to buy a USB adapter wouldn't be any better to my mind; it's not like this connector is only available from Nokia. But whatever the case, you buy a new adapter once. You have to deal with choosing between powering the N800 and using a USB device with it every time you use it. (Note that host mode tends to run the battery down pretty quickly if it's not connected to the charger; it's singularly annoying to have to stop what you're doing to charge the battery, and then go back to work.)

Google something innovative like 770 schematic; there are also apparently N800 schematics too (though I had thought there weren't when I posted above...).Yes, but your laptop isn't one of them. Did that ever strike you as odd?

Bringing up examples of devices that suffer no loss of functionality from being connected, and that have only one type of connection, makes it look like you aren't following Martin's or my explanations, but I don't know how to make it any clearer. There's a tradeoff you make by powering over a data link, and in a device as flexible as the N800, it winds up getting pretty ugly.



p.s.

A couple of technical forum points:

• The close tags use slashes, just like sgml or xml, not back-slashes.
• We're using at least a 7-bit encoding, so upper-case letters are quite acceptable.

The 2mm charger plug could be a special Nokia invention, but it's hardly difficult to find a charger with one of those plugs on. My local £1 shop sells USB multi chargers with them on.

The main reason for not doing charge-via-USB seems to be because of the internal memory cards. If you plug your NIT into a PC, what do you want to happen? To charge, to sync files or what? How can you tell it in a way that is non-technical and fairly obvious? You can't, can you?

Obviously you can't allow both the PC and the NIT to write to the flash at the same time, that'd be a horrible mess.

It would be nice if the NITs came with special USB cables that had a regular USB connector on the PC end, and then a Y at the other with the USB data and a mini jack plug for charging. They could do away with providing a mains charger then.

All this mess could be removed by natively supporting WIFI file transfers and then removing the USB connector all together. It'd be so much nicer if my N810 appeared on my Samba network so I could just drop files on it. I have tried this using SSH {SCP or RSync}, but it's really slow and prone to randomly stopping.

If it's prone to randomly stopping, you've probably got link-layer problems... sftp, of course, is slower than ftp, but I've used that with good success.

As for the special USB cable: one of those is available, but not from Nokia. It wouldn't do away with the need for a power adapter, though, because the power adapter that comes with it is 980mA, and USB is maximum of 500 mA. You'd consign yourself to slow charging, and inability to maintain a charge during heavy usage.

Also, ditching USB also ditches USB host-mode (which is another troublesome spot WRT charging over USB), and that's not a tradeoff that seems beneficial. Better perhaps is to get USB-networking to work on all versions of Windows, make that the default usage of USB, and support file transfer (probably via SMB) over that network. But charging still has to be separate to allow host mode to work well.

A similar situation exists with external hard-disks cases, as most drives require up to 1A.
The solution is to use a Y-cable (with 2 USB plugs), thus drawing 500mA * 2)...

I'm on travel and have been running my N810 off a usb charging cable for a week now and it never seems to get above 75% charge, (per the battery-status app). At home off the wall wart it would got to 100%. Is this to be expected?

While the USB charging adapter likely provides less power to your tablet than the bundled AC adapter, your tablet should eventually reach a full charge with either one. The exception to that would be if you're keeping your tablet busy enough while connected to the charger that all the incoming power goes to current activity rather than to charging the battery. For instance, playing media (especially streaming) at full volume and brightness can easily soak up all the juice a low power charger can provide.

Personally, I've used both a cheap knock-off and a genuine USB power adapter to charge my N800, and both easily charged my tablet fully.