Abstract: A mobile device is described that includes a control for activating a function of the mobile device. The function includes a Push-to-Talk function and/or a Push-to-Scan function of the mobile device. A processor executes the function when the control is activated. A transceiver is coupled to the processor. The transceiver is capable of communicating with at least one networked device over a local area network using voice over internet protocol (VoIP). A memory is coupled to the processor for storing instructions to execute the function by the processor. The processor executes the Push-to-Talk function in a first mode of operation and the Push-to-Scan function in a second mode of operation. The mobile device is part of a system that is also described. The system consists of a VoIP Push-to-Talk infrastructure, either server based or serverless. The mobile device described provides Push-to-Scan functionality over the existing VoIP infrastructure.