The TRICX-AIU is an audio interface unit designed to work with IP based switching systems such as the AWCSL TRICX. The unit links to the host PC via a single USB connector and over this link provides all the necessary signalling enabling the AIU to offer multiple audio inputs and outputs each switched by the appropriate push to talk input to the unit. As well as auxiliary, desk microphone and dual headset inputs the AIU also offers a dual loudspeaker output offering the user separate monitor and select loudspeaker options. The unit has been designed to be desk mounted and being of a sturdy construction can easily be mounted below the users PC monitor.