The hard part is getting a cable with the A sense, however this adapter is a good place to start:

(Links adjusted to use ASINs so should work)

http://www.amazon.com/gp/product/B000Y032X8

They also have a power adapter (the ultra-tiny to something much more common):

http://www.amazon.com/gp/product/B0009RFX24

(Note handling is charged once, so it is cheaper to get multiples to save on shipping if you can get them from the same place).

The above cable adapts the micro-B to the far more common mini-b and is small enough to carry with you.

For host mode, a mini-b to female-a is useful:

[url]http://www.amazon.com/gp/product/B000Y6UL5E

To make the micro-mini adapter cable into a host mode, carefully strip off the outer sheath and the metal shielding between the connectors. This will expose 5 wires - the usual red/green/white/black for USB, and brown for the host/perpheral sense.

Strip the insulation from the black and brown wires in the middle (carefully, using a lighter will melt - try not to burn - the insulation making it easy to strip).

Short the wires (and solder them!), and you now have a host mode cable. If you are ambitious , add a switch between the two wires so it can be used either way.

I didn't redo the shielding, but did use electrical tape over the wires.

Most "keychain" flash drives will work without external power. I keep a microSD in adapter in the female-a slot on my adapter chain so I can easily copy files betwen a PC and the n810 without having to worry about plugging in the n810 itself.

It will enumerate (recognize and use) hubs which can provide lots of power. You can even use that power to charge the N810 using the other adapter cable. It will give a "Hub not supported" notification. Then you can plug nearly any disk into the hub and it will mount. (you might need ext2/3 for Linux drives, it doesn't see mac partitions, but will recognize FAT iPods - will someone port GtkPod?).

Compiling more kernel modules adds more options. sr_mod.ko and cdrom.ko will allow you to access CD/DVD drives, but you will need to mount them manually. isofs.mod and ufs.mod will be needed to see files in most cases.

My EVDO modem (a UM-150) is recognized as is a serial adapter, both come up as /dev/ttyACM0, but there seems to be an interrupt problem with the cdc_acm.ko module - the serial adapter works (far better in a powered hub), but the UM-150 (requires powered hub) has problems with repeated characters or chatter. The UM-150's microSD is recognized without any problem though.

Good info

If amazon.uk don't have them then these USB dongles are available to the UK through dealextreme.com as well. With the dollar to sterling rates being the way they are today, you're in for a bargain!

Charging dongles are available in Poundland (at least, in the Croydon Pundland they are!) They do a number of them with a retractable USB charger cable, VERY good value for money.

Doesn't nokia sell a craddle or any pre-made cable to do so? That'd be surprising, no?

Well, this sort of works. In all cases I get the following message:

USB device not supported

USB thumb drives are however subsequently recognized. However, connecting a USB-CF reader and CF card gets this message:

Unable to connect, no file system available

The card in question does have a useable FAT file system. I've also tried other card readers, other cards, and in all cases get the - no file system available - message.

Ideas, thoughts, comments, suggestions; all welcomed. I'd really like to be able to use the N810 to view photos off the CF cards my camera uses.

Spoke too soon, did too little testing. Short version is that it works. Slightly longer version is that where the card was formatted seems to make a difference. I can now view non-raw images created on my camera. Takes a little while to fully render, but works quite well. Lots of connectors in the mix: micro to mini with the host mod, mini to standard, Female to Female adapter, and finally the CF card reader.

Hi tz1.
There is no need to tweak OS / kernel / drivers in any way ?
Is it just a matter of USB cable ?
XooH

For mass storage and at least the Linksys USB100M ethernet controller, they work with the stock setup. No kernel modules or modifications needed. A few things will need a powered hub (injectors don't work as the device says it needs X mA, and if that is too much the n810 will not connect it). Note even the iPod and some mass storage devices will need this. Also, Mac iPods won't work because they have both different partitioning AND use hfsplus for a filesystem.
About half of the flash keys i've tried and roughly half the CF/SD/XD card readers don't need the powered hub.

(One device which did need a kernel module worked much better with a powered hub, but would connect and be recognized without one).

Latest Experiments:

The WiSpy does connect (anyone up to porting the viewer program?), as does a Zeevo USB Audio to Bluetooth (looks like an audio device and is supposedly supported with esd).

Thanks tz1.
As my N810 is currently beeing on its way home (i.e. _MY_ home ;-) I'm interrested.
Unfortunately, neither Amazon nor dealextreme.com will ship those cables to France (yes, that's where I am).
Will keep searching, and if anyone has any info, will be of great value.
XooH

Google for "skn6252a" - that is the motorola part number (stamped on the connector) for the Micro-to-Mini adapter. Many, many places come up.

tz1 - WiSpy is the main tool that I would like to use... Have you tried the curses version of the tool?? That would suffice for me for the time being..