HDMI-CEC to USB and RS-232 bridge

-- protocol converter

NOTE: support for this device has been discontinued


This device has been discontinued and is no longer in stock. Special orders (quantity) or licensing options available.

The functionality of the HDMI-CEC to USB Bridge is detailed in this downloadable PDF (HDMICECtoUSBandRS232v2.0.pdf).


Both receive and send hex-codes on the single wire CEC bus present in HDMI cables. The USB tty (serial-port) and RS-232 serial device is compatible with both Windows and Linux without custom device drivers. Though not officially supported, it has been demonstrated to work with OS-X.

NOTE: To use this device as a bridge to RS-232 (9600 baud on 3-pin Phoenix connector), it must be powered via the USB port using either a connection to a PC or a USB mobile phone wall charger.

This device allows one to monitor and send CEC hex codes on the single wire bus using a USB tty (serial-port) or RS-232 serial port. Compatible with Windows (validated on XP, Vista and Windows 7) and Linux (validated on Ubuntu distribution) without additional host drivers. Please note that even though a custom driver is not needed for Windows, you will still need the device’s '.inf' file to match the product’s VID and PID to the Microsoft driver (downloadable here).
UPDATE: Windows 8 requires that the ".inf" file is signed. If you need to load the driver on a Windows 8 machine, there is a self-signed version of the driver. Because it is self signed, the installation will give you a warning that it is from an un-trusted source. Regardless, there are no binary files being shared, the .inf simply points to already provided Microsoft drivers (that are presumed "safe"). The zip file containing the self-signed driver is here

The CEC bus is sampled every .1ms using a microprocessor. When a start bit is detected and a complete frame read, the contents are converted to plain text hex digits and forwarded to the host through a USB connection. As an alternative to USB, the device also provides a RS-232 protocol interface via a 3-pin Phoenix connector.

The USB device is detected by the host as a tty serial device or port. Reading from this port allows a program to see everything that is passed on the bus. Writing to the port allows a program to place complete frames onto the bus.

For a detailed description of this device, command set, and how to use it, refer to this downloadable PDF (HDMICECtoUSBandRS232v2.0.pdf).

The detailed specification of the HDMI-CEC protocol and bus can be found here.

This device has been demonstrated to work with TVs from Samsung, Sharp, Sony, Toshiba, LG, Panasonic, and Mitsubishi. TV CEC capabilities vary widely. Many recent models can be powered on, off, and have the external HDMI input source chosen via CEC. If you additional questions, please see the contact page and write us an e-mail.