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RS-232 Serial Adapter for Android Devices


  • Android USB 2.0 Full-Speed Host to industry standard RS-232 DB9M serial port
  • Supports UART interface with RX, TX, RTS and CTS
  • RX buffer size 5512 bytes; TX buffer size 256 bytes
  • Supports baud rates up to 460.8kbps, 921.6kbps optional
  • Use with any Android platform supporting Android Open Accessory Mode (typically 3.1 or above)
  • ±15kV ESD protection on USB data lines and all RS-232 signals
  • Status and fault LEDs including external power, charging status, and USB status
  • Supports USB charging for Android devices
  • Type A USB connector features industrial strength high retention design
  • Latching +5V external power input connector with external regulated power supply
  • Industrial operating temperature (-40°C to +85°C) standard
  • A hard line wired connection eliminates security concerns associated with Wi-Fi and other radio frequency solutions
  • RoHS Compliant
  • Designed, made, supported, and manufactured in the USA


  • RJ12 female for RS-232, including GPS signals on RJ12 and J5 connector
  • RJ45 connector with Cisco pinout
  • RJ12 connector
  • Baud rates up to 921.6kbps
  • RoHS Available. Please contact us for ordering information

The ANDROID-232 is USB serial interface board which allows users the ability to control legacy RS-232 devices directly from modern Android devices. The ANDROID-232 uses the Android Open Accessory protocol to convince an Android device that its onboard USB port (normally limited to USB "slave" or "OTG" modes) is actually an RS-232 port. This two way data port allows external hardware to control the Android unit or for the Android unit to control external hardware. Onboard data buffers minimize streaming jitter, and full hardware flow controlled serial data up to 921.6kbps is supported (a max of 115.2kbps without flow control). Onboard circuitry will provide power to charge your Android device while connected. Multiple status and fault LEDs complete the package, and allow simple and convenient confirmation of operational state.

This small industrial/military grade product features industrial temperature operation (-40°C to 85°C) ideal for outdoor applications, harsh industrial surroundings, or military use. Also, a hard line wired connection eliminates security concerns associated with Wi-Fi and other radio frequency solutions. A Type A industrial strength USB connector provides high-retention that complies with class 1, Div II minimum withdrawal requirements. The ANDROID-232 is feature-rich and allows for the connection of RS-232 serial devices—ideal for a variety of applications such as POS, gaming systems, retail, hospitality, automation, kiosks, defense industries, lighting, or any other application requiring the connection of RS-232 serial devices to an Android compatible system.

High Retention USB Connector

The ever-growing presence of USB in the industrial/military marketplace has driven the need for USB connections to be reliable, dependable, and unfailing. Gone are the days of loose USB connections. A type A USB connector is used on the ANDROID-232 which features a high retention design that complies with the class 1, Div II minimum withdrawal requirement of over 3 pounds of force (15 Newtons). This connector has an orange color-coded insulator to quickly differentiate it from standard USB connectors. Using these USB connectors increases reliability in your system and ensures a tight connection.


  • Control high-tech electronics in military and industrial environments
  • Connecting Android phones to serial accessories
  • Connecting Android tablets to serial accessories
  • Controlling instrumentation from Android devices
  • Home automation via Android devices
  • Industrial automation


Available accessories include a broad range of cable assemblies and screw terminal boards for quick and easy connectivity. The ADAP9 accessory provides a screw terminal connection to break out the RS-232 signals on the DB9M connector for connections to non-standard RS-232 pinouts. Special order items such as conformal coating, custom software, and more, are also available.


The ANDROID-232 product includes an Android sample program, with source, which operates within the Android Open Accessory protocol, available on all devices running Android 3.1 or higher (some 2.3.4 ROMs are supported). This program will allow you to verify proper operation of the ANDROID-232 device, including sending and receiving RS-232 data. A Python test program that can cooperate with the Android sample program to verify proper receipt of data as transmitted is also provided. In any operating system you can communicate through the ANDROID-232 using the standard communication terminal program of your choice; in Windows we provide, and highly recommend, a very powerful terminal program called "WinRISC". Windows samples in a variety of programming languages can be used to jumpstart your Serial COM programming (with full source code).

Available Reference Manuals

Available Software Downloads

Available Datasheets

Drivers and Downloads

Full list of available Downloads: Software Packages, Drivers, Manuals, and other documents

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.


Communications Interface

  • I/O Connection: DB9M (optional RJ45 or RJ12)
  • Serial Port: RS-232 signals RX, TX, RTS, CTS, GND
  • Serial Data Rates: 460.8kbps (921.6kbps available), 115.2kbps without RTS/CTS flow control
  • ESD Protection: 15kV on all signal pins
  • Character Length: 7 or 8 bits
  • Parity: Even, Odd, None, Space, Mark
  • Stop Interval: 1 or 2 bits
  • Flow Control: RTS, CTS

Bus Type

  • USB 2.0 Full-Speed
  • USB 3.0 Compatible
  • USB 1.1 Compatible

A type A USB connector with a high retention design that complies with the class 1, Div II minimum withdrawal requirement of over 3 pounds of force (15 Newtons) is used.


  • Operating Temperature Range: -40°C to +85°C
  • Storage Temperatur Range: -40°C to +85°C
  • Humidity: 5%-95%, non-condensing
  • Board Dimension: 1.900 x 3.750 inches


  • External AC/DC 5V regulated adaptor is included
  • External Power: +5VDC @ 1A external power required
  • USB Charging Power: Up to 500mA provided to Android device

Connector Pin Assignments

The ANDROID-232 has a 9-pin DB9 connector provided for I/O connections. Connector pin assignments are listed below.

Regulatory Compliance

  • This product is designed to be in full compliance with CE requirements.
ModelPrice (USD)

Ordering Guide
ANDROID-232RS-232 serial adapter for Android devices
ADAP9Screw terminal breakout board with DB9F connector. $19
Model Options (call for pricing)
-S01RJ12 female for RS-232, including GPS signals on RJ12 and J5 connector
-F921.6kbps baud rate
-RJ45RJ45 connector with Cisco pinout
-RJ12RJ12 connector
Acquisition, Control, Communication: Engineering and Systems