A PC/USB Adapter that allows users to use their headsets with a PC/Computer softphone (like Microsoft Skype for Business)- The APU-76 is compatible with CS500 series wireless headsets (CS510, CS520, CS530, CS540, C054, C052). Also compatible with the Mitel 6867 and Mitel 6869 HID1 desk phones- Compatible with Yealink SIP-T58V, SIP-T58A, SIP-T56A - Based on V83- Compatible with Yealink SIP-T54S, SIP-T52S, SIP-T48S, SIP-T46S, SIP-T42S, SIP-T41S, SIP-T53, SIP-T53W, SIP-T54W, SIP-T57W - Based on V84