# Using Android Accesory mode to access a USB serial device, use a VNC2?

In a current project we use an Android application that talks to a USB Serial device (which speaks the Prolific USB serial protocol). This works fine with Android devices that support USB Host Mode, but there aren't too many of those.

So, I would like to use this device with a device that only supports Android Accessory mode, by putting a bridge device in between: this device speaks the Android Accessory protocol on one side, and the Prolific USB Serial protocol on the other. So,

+---------+       +--------+           +----------+
|         |       |        |           | Prolific |
| Android | ----> | Bridge | --------> | USB-     |
| Device  | <---- | Device | <-------- | serial   |
|         |  ADK  |        |  Profilic |          |
+---------+       +--------+  USB      +----------+
Protocol


In which the incoming data stream from the serial device is forwarded to the inputsream of the ADK device, and vice versa.

I plan to base this device on an FTDI VNC2 (with the V2DIP2, there's a development board that has all the hardware I need for this).

Is this chip indeed the best choice for this kind of bridge? Is there something else on the market that perhaps does this bridging out of the box?

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Is this for a one-off, or low volume project, or for mass production ? I'd guess, it's the latter since you are adopting a DIY route, since there are several ADK boards which can perform the bridge role. On developer.android.com/guide/topics/usb/adk.html the section on "Android Open Accessory compatible development boards..." –  icarus74 Feb 23 '12 at 17:25
It's for low volume production, in which I'm shooting for the simplest (and most cost effective) option. I am aware of the more powerful boards, but since I only use them as a conduit, I could probably get by with something simpler. –  Angelo van der Sijpt Feb 23 '12 at 17:39