Turn infrared reception on or off
If your Mac has infrared (IR) reception, you can turn it on or off in Security & Privacy preferences. When you turn on IR reception for your Mac, any IR device close to your Mac can control it. You can turn IR reception off to prevent unwanted control of your Mac or to prevent pairing with an IR remote control.
On your Mac, choose Apple menu > System Preferences, click Security & Privacy, then click General.
Click the lock icon to unlock it, then enter an administrator name and password.
Select “Disable remote control infrared receiver” to turn off IR reception, or deselect it to turn on IR reception.
To set your Mac to respond to the commands of a specific remote control, click Pair, then follow the onscreen instructions.