CEC Adapter — LG TV Not Responding to Commands

Modified on Wed, 29 Apr at 10:21 PM

If your LG TV does not respond to any CEC commands from the USB-CEC Adapter despite Simplink being enabled, there are several LG-specific settings that can interfere. This article covers the most common causes and their fixes.

Step 1 — Confirm Simplink Is Enabled Correctly

On LG TVs, CEC is called Simplink. Go to Settings → General → Simplink (HDMI-CEC) and confirm it is set to On. On some LG TV models there is also an Auto Power Sync or Auto Power option within the Simplink settings — enable this as well. Without Auto Power enabled, the TV may acknowledge CEC presence on the bus but not act on power-related commands.

Step 2 — Check the Set ID Setting (Commercial Displays)

LG commercial displays (including LG Business/Pro displays often used in installations) have a Set ID setting. The Set ID must be set to 1 for standard CEC communication to function correctly. If it is set to 0 or a value other than 1, CEC commands may be ignored.

Find the Set ID setting in the TV's service menu or installation settings. On commercial LG displays this is typically under Settings → General → Set ID.

This Set ID issue specifically affects LG commercial and Pro displays. Consumer LG TVs do not typically have this setting and it is not relevant to them.

Step 3 — Check Power On Delay Settings

Some LG TVs and commercial displays have a Power On Delay setting that staggers power-on when multiple devices are connected. If this delay is set too high, the TV may appear unresponsive to power-on CEC commands that are sent before the delay expires. Find this setting in Settings → General → Power → Power On Delay and either reduce it or set it to 0.

Step 4 — Confirm the CEC Bus Scan Shows the TV

Run a CEC bus scan to confirm the TV is being detected at all. Open a command prompt and run:

(echo scan & echo quit) | cec-client -d 1

The scan output should show at least two devices — the adapter itself and the TV. If the TV does not appear at all, confirm the HDMI cable is firmly seated and Simplink is enabled. If two devices appear but commands still fail, proceed with the settings above.

Step 5 — Try a Different HDMI Port

On some LG TV models, CEC is only fully active on specific HDMI ports. If possible, try connecting the adapter to a different HDMI port on the TV and retest. HDMI port 1 is typically the primary CEC port on LG televisions.

LG TV still not responding?
Contact Pulse-Eight support with your LG TV model number, libcec version, and the output of the CEC bus scan.

UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com