31Connecting and Using a Source Device22 Connecting and Using a Source DeviceConnecting to Headphones (S22E390H / S22E393H / S22E395H PLUS / S24E390HL /S24E393HL / S24E395H PLUS / S27E390H / S27E393H / S27E395H PLUS)Do not connect the power cable before connecting all other cables. Ensure you connect a sourcedevice first before connecting the power cable.1 Connect an audio output device such as headphones to [ ] port on the product.This function is only available in HDMI mode.The sound could only be heard when using the HDMI to HDMI cable.