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Two-way adapter links Android devices to RS-232
Published:  10 February, 2014

US-based Acces I/O Products has produced a circuit board that allows Android devices, such as smartphones and tablets, to communicate directly with RS-232 devices. The two-way Android-232 data port allows external hardware to control the Android device, or the device to control external hardware.

The $139 board uses the Android Open Accessory protocol to convince the Android device that its onboard USB port (normally limited to USB slave or OTG modes) is actually an RS-232 port. It supports serial data up to 921.6kbps (or up to 115.2kbps without flow control). Onboard circuitry provides power to charge connected Android devices.

Acces says that the hard-wired connection eliminates the security concerns associated with wireless systems.

The board converts an Android USB 2.0 full-speed host to a standard DB9M RS-232 serial port. Accessories include cable assemblies and screw terminal boards. One provides a screw terminal connection to break out the RS-232 signals for connection to non-standard RS-232 pinouts.

Acces I/O's board links Android phones and tablets directly to RS-232 devices

The board has an operating temperature range of –40°C to 85°C, and is said to be suitable for harsh industrial surroundings or outdoor applications. Status and fault LEDs indicate its operational state.

The board comes with an Android sample program which operates within the Android Open Accessory protocol, on devices running Android 3.1 or higher. The program allow users to verify proper operation of the device, including sending and receiving RS-232 data.