Series audio processor cords make it possible to connect virtually any desk phone with s Quick Disconnect corded headsets. Even though the headset and desk phone may be plug-compatible, the wiring is determined by the individual telephone manufacturer. Series cords feature eight separate wiring schemes including three with built-in microphone amplification. Just connect the cord and the headset through the Quick Disconnect plug and flick the slider from one position to the next until a dial tone is heard. Its as simple as that! Series cords feature eight microphone volume settings to ensure that the volume of all outgoing calls is at the same user defined comfortable level.