To connect a cable box to an LG Smart TV, plug an HDMI cable from the cable box's "HDMI OUT" port into any "HDMI IN" port on the TV, then select that HDMI input on the TV. This single cable carries both video and audio, so no other wires are needed for the connection.
Before You Connect the Cable Box to Your LG Smart TV
Turn off both the LG TV and the cable box before handling any cables. This protects the HDMI ports from electrical surges and prevents accidental damage to the connectors. The only cable required is an HDMI cable, no component cables, RCA cables, or adapters are needed. On the back of the cable box, locate the port labeled "HDMI OUT." On the back or side of the LG TV, find the ports labeled "HDMI IN" (usually numbered HDMI 1, HDMI 2, etc.). Make sure you can identify both ports clearly before proceeding.
Connect the HDMI Cable to the Cable Box and TV
Take one end of the HDMI cable and insert it firmly into the "HDMI OUT" port on the cable box. Then take the other end and insert it into an "HDMI IN" port on the LG TV. Note which HDMI port number you used (for example, HDMI 1 or HDMI 2), you will need this number in the next step. Push both connectors in until they click or sit flush; a loose connection can cause intermittent signal loss.
Power On and Select the Input Source
Turn on the cable box first, then turn on the LG TV. On the LG remote, press the "Input" button (sometimes labeled "External Input") or the "Home" button. If you pressed "Home," navigate to "Source" or "Inputs" in the on-screen menu. From the list of sources, select the HDMI port number that matches the one you used for the cable box (e.g., HDMI 1). Press "OK" or "Enter" to confirm. If a "New device connected" message appears on the screen, press "OK" on the remote to accept it. The cable box's signal should now appear on the TV screen.
Troubleshoot 'No Signal' or 'Unsupported Resolution'
If you see "No signal" on the screen, first verify that the HDMI cable is fully inserted at both ends and that you selected the correct HDMI input. If the message persists, the cable box may be outputting a resolution the TV cannot display. Access the cable box's settings menu (using the cable box remote) and change the output resolution to 480p, 720p, or 1080i. These standard resolutions are universally compatible with LG Smart TVs. If your cable box is an IPTV set-top box (one that receives service over the internet rather than a coaxial cable), ensure it is powered on and connected to the internet, without a network connection, the box will not deliver any channels, and the TV may show a blank screen even with the correct input selected. If you are using a traditional coaxial connection instead of HDMI, you will need to connect cable to LG smart TV and run a channel scan to receive programming. If you are cutting the cord entirely, you can connect antenna to LG smart TV to pull in free over-the-air broadcasts without any subscription.
Set Up the Universal Remote Control (Optional)
On LG Smart TVs running webOS 4.5 (2019 and later models), the universal remote control function for the cable box may be set automatically when connected via HDMI, the TV detects the box and configures the remote so you can control volume and channel changes without a second remote. Note that universal remote control settings are only possible when the LG TV has a network connection, either Wi-Fi or an Ethernet cable plugged into the TV's LAN port. Once set up, you can use one remote for both devices, which also gives you quick access to the channels available on an LG smart TV without juggling multiple remotes. If the automatic setup does not trigger, navigate to Settings → General → Universal Remote Settings and follow the on-screen steps to pair the cable box manually.
