USB Device Not Recognized? Troubleshooting USB Extenders and KVM Systems
A USB device may work normally when connected directly to a computer but stop working after a USB extender or KVM system is added.

In the previous article, we discussed the nature of ARC, its differences from Audio Extractors, and the advantages each offers in different scenarios. In this article, we will explore the technology of HDMI ARC and the differences between ARC and eARC. We also include some useful tips for using ARC audio and an introduction to other common home audio interfaces.

Read the last article: How to Connect External Speakers to TV: HDMI® ARC vs. HDMI® Audio Extractor
HDMI ARC (Audio Return Channel) was introduced with HDMI 1.4. This feature allows audio to be sent back from a TV to an audio receiver or soundbar through a single HDMI cable, eliminating the need for an additional audio cable. For instance, if you are using a TV app like Netflix, ARC allows the TV's audio to be output directly to the audio system via the HDMI cable, providing better sound quality.
HDMI eARC (Enhanced Audio Return Channel) is an advanced version of ARC, introduced with HDMI 2.1. eARC offers higher bandwidth and speed, supporting higher-quality audio formats, including Dolby TrueHD, DTS-HD Master Audio, and higher-resolution audio. Additionally, eARC supports automatic detection of audio sources and improved audio synchronization management. This means eARC not only provides better sound quality but also ensures more precise audio-video synchronization.
ARC and eARC differ in many features. You can find answers to questions like "Do all HDMI cables support ARC?" in the below table.



Besides ARC/eARC, there are more audio transmission technologies commonly used in home audio systems.
SPDIF (Sony/Philips Digital Interface Format) is a digital audio interface developed by Sony and Philips. It can transmit two channels of uncompressed PCM audio or compressed 5.1/7.1 surround sound. SPDIF can use either optical fiber or coaxial cables as transmission media.
Like eARC, SPDIF can preserve the original audio quality. If your TV has an SPDIF output, it can be connected to an amplifier.

TOSLINK (Toshiba Link) is an optical transmission technology based on the SPDIF standard, developed by Toshiba. It can also transmit two channels of uncompressed PCM audio or compressed 5.1/7.1 surround sound.
Unlike SPDIF, TOSLINK uses optical fiber cables exclusively, providing better interference resistance and longer transmission distances.

Wireless transmission is a better option when you only need to play audio through an amplifier without a TV display.
Many Bluetooth audio receivers are available in the AV market. You simply connect the receiver to the amplifier, which can then receive audio via Bluetooth and output it to the speakers. Besides, Apple's AirPlay technology is increasingly used in various smart TVs and amplifiers, offering superior uncompressed audio quality compared to Bluetooth.

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A USB device may work normally when connected directly to a computer but stop working after a USB extender or KVM system is added.
AV requirements in a medical simulation center go beyond recording a training session. In addition to room camera feeds and audio, a session may require recording patient vital signs, ultrasound images, or displays from other equipment. Some content may need to be sent to a control room or observation area for live viewing and later used during debriefing.
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