Hello everybody,

I need to build an application on a phone which can access data on an external device with USB interface (CDC class) or SPI interface.

I can see two possible approaches:
a. use an OTG enabled phone
b. use an external MCU board with USB host functionality to work as a bridge between the phone and my peripheral

I am assuming there is no way to directly access an external SPI device from a phone. Is this correct?

I would like to ask for suggestions about the best approach and maybe pointer to more information about the following issues

Approach a.
Is there an OTG-enabled phone with built-in support to access a CTC class device?
Is it possible to develop in J2ME or do I have to go at Symbinan level?
From the searches I made I only found this link for about using OTG http://blogs.forum.nokia.com/blog/ka.../usb-on-the-go on the Maemo platform, but nothing on S40/S60 (even if I found some S40 devices which do have OTG in their feature list). Is N810 the only way to go?

Approach b.
What device class/interfaces are implemented on phones for serial communication? are these standard interfaces? Is there any documentation which allows to create an USB host driver? or is there any vendor that can provide/implement USB host support on an MCU-based platform with USB host capability?

I am new to the forum and to phone development so please bear with me if I asked stupid questions or in the wrong forum.

Thank you in advance