CEC Adapter monitoring mode (Windows)

Monitoring mode allows you to observe all CEC messages being sent on your HDMI network in real time. This is useful for diagnosing why a CEC command is not working, checking what commands your TV or devices are sending, and debugging integrations with media centre software or home automation.

Running Monitoring Mode on Windows

cd "C:\Program Files\Pulse-Eight\USB-CEC Adapter"

cd "C:\Program Files (x86)\Pulse-Eight\USB-CEC Adapter"

cec-client -m

Understanding the Output

Each line of output represents a CEC message, for example:

TRAFFIC: [ 15:45:22.417]     >> 0f:36

The numbers after >> are the raw CEC command in hexadecimal. You do not need to decode these to use monitoring mode for basic troubleshooting. The key things to look for are:

• Are any messages appearing at all? If nothing appears when you press buttons on your TV remote, CEC may not be enabled on your TV. Check your TV's settings for a CEC option (Anynet+, SimpLink, Bravia Sync, etc.) and ensure it is turned on.
• Is the adapter detected? If cec-client reports no adapter found on startup, check the USB connection and that libcec is correctly installed.

Running Monitoring Mode on Linux / Raspberry Pi

On Linux or Raspberry Pi with libcec installed, run the same command from a terminal:

cec-client -m

If you have multiple CEC adapters available, specify the adapter:

cec-client -m /dev/ttyACM0

All cec-client Options

To see all available options for cec-client, run:

cec-client -h

Related Articles

• Getting Started — CEC Adapter
• Which TV Power Control Method Should I Use?
• Upgrading the Firmware of the CEC Adapter
• CEC Adapter — Setting Up libcec on Linux
• CEC Adapter — Setting Up libcec on macOS
• CEC Adapter — Using libcec with a Raspberry Pi