The closest you are likely to get for isp datasheets without asking nicely

http://www.stericsson.com/technical_...ISP1704A_2.pdf

Offhand the apparent notable difference is charger detect pin polarity (1704 only does high and 1707 does low / high.)

Er, that chip is a BGA, and the ID pin (D3) is right in the middle.
I think SpeedEvil made quite an understatement when he said on the wiki that this would be a "challenging" rework job.. @_@

Even with the schematic it could still be next to impossible with a multi-layer PCB.

This is a real shame.. I was literally just about to buy one of these as I am developing some robot control software for the USB AVRs. 3G connection and fast processing on an n900 would have been wonderful..

just a crazy idea for a workaround:

implement USB/IP (http://usbip.sourceforge.net/) on the N900 and on
an external microcontroller with USB host ports (i.e. a smarter USB hub),
e.g. http://microcontrollershop.com/produ...oducts_id=2649,
and connect them via USBnet (N900=slave, hub=repeater)?

titan, that ain't crazy at all - previously mentioned workarounds were using a similar concept - only the "router" was a bluetooth device (but none was found, that would provide bluetooth connection and an usb host port)...

this two-port thingie seems to be a nice workaround - if it is fast enough, then using usb/ip (didn't know someone already invented that :-) ) you could bring usb host functionality to virtually any device, if you can port the usb/ip stack to the kernel, of course...

and if it is possible to to flash the device with appropriate firmware... well, there are some "if"s... but it's a start of new solution - if other approaches fail...

ok, let's call this solution "USB/IP hub" (tm).
after some googling it turned out to more feasible than I initially thought:

USB/IP is implemented in Linux 2.6.28 (staging) and consists
of a pseudo USB driver on the server (the hub, where the USB device is connected)
which redirects all IO through a user-space daemon to the client (N900), which
has a simple virtual HCI and standard USB device drivers in the kernel.

The simplest solution would be have Linux (e.g. 2.6.28) on both sides.
We could already try that out by recompiling the N900 kernel and connecting it to a USB/IP enabled Linux desktop via USBnet/wifi/bluetooth.

If that works reasonably well the next step would be to look for a small embedded Linux (2.6) board which has more than one USB host port and can be powered by battery.
for example, http://www.tigal.com/product.asp?pid=1333&lang=EN (too large),
http://eshop.acmesystems.it/ or, my current favorite:
http://www.ic-board.de/product_info....0-OEMplus.html
features:
Linux 2.6.28
3x USB2.0 High Speed Host (one reserved for connecting to the N900)
10/100 MBit Ethernet (LAN port for the N900)
small size: 40mm x 35mm x 6mm, weight 50g ! (w/o USB ports and battery)
if you want you could even add a SD card reader, serial ports, LCD etc.
you could also connect a Bluetooth module via SPI and have 3 free USB host ports.

the only drawback: the price
but if you build it yourself (eagle files are free) I'm sure it's much less and
sparkfun.com is willing to do mass production for cool projects (UBW32).

It contains a very attractive USB controller http://www.stericsson.com/product/222228.jsp
and with an appropriate battery we could not only power the USB devices
but also charge the N900.

The advantages would be :
* up to 3 USB host ports with power supply
* LAN port
* no need to hack the N900 USB controller
* minimal software changes: compile existing USB/IP
code into client and server
* could also be used as a USB extender (USB over Internet)
or with other computer or Windows

cheers, (dreams to be continued in my bed)

USB over IP over USB? Too easy. May be it is reasonable to add VPN? we have openVPN r n900. USB over IP over VPN over IP over USB.

Don't forget USB over IPoAC (RFC 1149/2549) or IP over Status LED.

seriously, if you already need one of those embedded Linux boards with USB
for other purposes (e.g. robot control), then the USBhost over IP over USBnet/Bluetooth/Wifi could be a viable but expensive solution.

I suppose USBnet would have the lowest latency, maximum bandwidth and lowest power consumption of those three.

I think this is a very cool idea.
I think the USB over IP method could be used for a lot of different cool things. I'm hoping that a USB DVB-T adapter could be used for example (provided the bandwidth over wifi is sufficient ).

I intend to start my experimenting on my desktop PC.
Some links with how-to's:
http://howtoforge.com/how-to-set-up-...h-debian-lenny
http://howtoforge.com/how-to-modify-...over-ip-server

I also came across some ready to go images for the linksys NSLU2 device. That could be an easy and cheap solution to start experimenting with embedded USB over IP server solutions:
http://usb-server.com/nslu2.html
http://www.nslu2-linux.org/wiki/HowT...sbIpOnTheNSLU2
http://sourceforge.net/projects/usbi.../topic/1786127

I don't have a NSLU2 yet, so maybe other people could give their view about if that is a could way to start.

For example, if you use the tiny
http://www.gumstix.com/store/catalog...roducts_id=211
http://www.gumstix.com/store/catalog...roducts_id=230
you would have Ethernet, 2x USB host and DVI output via HDMI !!
(just run a VNC client on the board and x11vnc on the N900)
So you could even connect a monitor without TV-out or run
a X server with higher resolution on the embedded Linux.
Or with http://www.armadeus.com/english/prod...rds-apf27.html
you could do crazy stuff with the FPGA (motion tracking?)
and have 3x USB host, Ethernet etc
cool! please keep me posted.
I guess we would first need to compile a custom kernel with the full USB stack for the N900 but that's currently impossible (please vote for bug https://bugs.maemo.org/show_bug.cgi?id=7972)
wow! that company has been selling the USB/IP stuff for over two years.
so it be must already be working well enough.

How about a bluetooth USB hub?

http://www.inspector-gadget.co.uk/blog_134.shtml