In my last post I wrote about local connectivity - this time I'd like to continue the topic and look into USB OTG possibilities that IMHO are not well advertised to the users and developers. Generally, almost all smartphone manufacturers are on the same level taking into account hardware (e.g. the same ARM processors, memory chips and other I/O components) - the biggest difference lies in the software/OS/integrated services and look&feel of the device. Of course, the manufacturers have many opportunities to improve the hardware/software (do you remember my post "Japanese vs European smartphone features" or "How future displays for mobiles may look like?"?). IMHO, the next big thing after touch (WOW factor guaranteed!) may be USB host feature (also called USB OTG or USB On-The-Go).

No one should be surprised that we can connect different USB accessories to our PCs, but some may be amazed that the same idea works on several mobile devices. Let's start with Maemo platform. With the help of on-board USB OTG chip, F-F USB adaptor and "USB Control" application (like Kate's usb-otg-plugin) you can connect for example:

* normal PC keyboard


* USB mass storage device (e.g. your smartphone, pendrive, digital camera, various digital audio players & portable media players)


* USB toys (like little fan, LED light, etc.)


The limitation lies in A) power consumption (not enough current to supply any type of USB accessory, in this case USB HDDs, USB CD burners; according to FN, N810 can power an external accessory with a maximum of 100 mA; a standard PC USB host may output up to 500mA per USB port), B) software/drivers (like tv tuner, printer, scanner, mouse support; some USB Hubs are supported after recompilation of the kernel which is not a perfect solution for the end-user). I have no doubt that this technology will be improved in the future (don't forget that USB host was rather hidden feature of internet tablets at the beginning). I eager to know whether there're some improvements in this matter in Maemo 5 devices like N900, so don't hesitate to post comments to this blog as soon as you get one!

And other mobile platforms?
It's a pity that we still can't play that way with USB host mode on S60 smartphones (AFAIK, USB OTG extensions were intoduced in Symbian 9.3; OS provides the support within its framework, but the provision of USB Host stack and drivers is left to licensees and partners). I hope that the idea I presented more than two years ago will be introduced in S60 and it will move beyond current possibilities (USB peripheral classes supported on S60: Wireless Mobile Communications Device class for serial communication with PC - used by Nokia PC Suite, Mass Storage class, Still Image Capture Device class, PictBridge/Picture Transfer Protocol, Media Transfer Protocol). USB OTG is available on selected Series 40 devices (USB Host classes supported: Digital Audio Class, HID class + USB peripheral classes). Linux-based Android should get USB OTG too. I've got a feeling that USB host (implemented for a rich functionality) may become a distinguishing feature of internet tablets for some time, but if I am not wrong, we may see similar functionality on S60 too. Till then, power users can use such adapters to have access to mass storage devices through normal microSD slot. 

This may sound crazy, but imagine that you get a monitor, mouse and keyboard, USB Hub, Nokia Internet Tablet, then hook up everything only via USB and you suddenly have a desktop-lite PC. And that is only the beginning...