Compatible with many home stereo setups and professional music studios, headphones and headsets equipped with 6.35-mm jacks offer superior fidelity and sound quality for end users. Also known as phone plugs or one-fourth-inch headphones, these advanced audio interfaces were first used to provide voice connectivity in phone switchboards Compatible with many home stereo setups and professional music studios, headphones and headsets equipped with 6.35-mm jacks offer superior fidelity and sound quality for end users. Also known as phone plugs or one-fourth-inch headphones, these advanced audio interfaces were first used to provide voice connectivity in phone switchboards