FTDI FT311D/FT312D USB Host to UART COM Port Utility.
Android Honeycomb (3.1) and later versions support Android Open Accessory Protocol, which can receive and send data from an Android accessory without additional drivers. The utility is for FT311D/FT312D (USB Android Host chip) which is configured to be a USB to UART device.
The application will be popped automatically when you plug the FT311D/FT312D Android Open Accessory devices.
• Suitable for use on any Android platform supporting Android Open Accessory Mode (Typically 3.1 onwards, however some platforms may port Open Accessory Mode to version 2.3.4)
• Basic UART interface with RXD, TXD, RTS, CTS pins option.
• Provide general HyperTerm UART utility; easily adaptable to a console function.
• Support CTS/RTS Flow control
• Support Baud from 300 to 921600 with CTS/RTS flow control
• Support Baud from 300 to 115200 without flow control
• Save file and Send file functions support XModem, YModem and ZModem file transfer protocols.
• FT312D enlarges the UART RX buffer size to 5512 bytes for enhanced UART data streaming performance. FT311D RX buffer is 512Byte.
• USB Plug and Play
• Provide power source to the Android device via the Y-cable configuration.
• USB 2.0 Full Speed compatible.
• USB error and over current indicator.
• Suitable for TTL, RS232, RS422,or RS485 depending on the transceiver used in conjunction with the FT311D or FT312D.
You can see more details in FTDI web.