I wonder if your USB port isn't putting out enough current to charge the N810. Does the N810 giving you a charger connected indication when you plug in the fake cable?

I just received three of the CA-100 "knock-offs" from DealExtreme. My n800 charges fine with it. Also, the connectors fit snug and there is no heat given off of the cable. (There shouldn't be since there are no electronic components to dissipate heat and only wimpy current is passing through the wiring).

It is quick possible that DealExtreme had some "quality issues" with a previous supplier, but it now working with a better one.

These cables are a great idea, since they're small and take advantage of the regulated 5V power supply in the typical PC. Being dirt cheap is nice too.

A regulated 5V power supply is not what you need to charge an N800; that's why you can wind up with noticeably non-wimpy current flowing, and resultant burning things.

I respectfully disagree. According to usb.org's website, a USB 2.0 port can only supply 500mA of current. This is less current than what the Nokia-furnished AC adapter provides. If you connect something that draws more than 500mA (which is half of one ampere), the PC shows some type of error message and the port power is disabled. The port would then need to be re-enabled in some manner (or PC rebooted).

Since a USB port offers lower current, charging an IT with it is slower than with the AC adapter.

In practice, substantially greater current can be drawn by a non-conforming device, because most PC-class hardware doesn't monitor actual current flow. (If current were actually monitored, these cables would only get 100mA, because, being plain wires, they cannot make additional current requests as the USB standard requires of devices needing more power.) From the specifications, it may be inferred that the charger is used in the 3.5V - 5V range, so it's likely to draw substantially more than the rated 500mA to bring the voltage down out of regulation, in the absence of an overload detection and cutoff.

Additionally, even if a USB source were to act as a 5V regulated source, with a current limit (rather than an overload-shutoff) at 0.5A, that's still not correct for the tablets; the Nokia 2mm charging interface requires a minimum open-circuit voltage of 5.7V, and a minimum corner voltage of 5.54V, at 300mA. It would work, in all probability, but it's not correct.

BTW, I posted a link to the specifications for the Nokia 2mm charging interface earlier; in case you haven't read those, that's what I'm basing my information on.

mine burned after about a year of usage

I have this cable CA-100 and it really works with my N810 (but its slower then usual charger, about 1.5 times). I use notebook USB port. Maybe your usb port have not enough power for charging IT.