If your system is a closed-mic private radio system or VoIP (Voice over IP) system, operators must send a Request to Talk (RTT) or a Priority Request to Talk (PRTT) message. Then, dispatchers must set up a voice call before the operator can talk to dispatch on the radio or by VoIP.
In a closed-mic system, operators cannot hear each other on the radio without a dispatcher setting up the call. Dispatchers control who is on the channel at any time. Use the guidelines developed within your transit agency to determine when a priority message (PRTT) is appropriate.
To send an RTT or PRTT message, touch either the or the icon in the menu bar and wait for a response from a dispatcher. These icons are active only in closed-mic systems.
Unlike private radio systems that can be configured for Open Mic, where everyone hears all calls and operators can use the radio at any time, VoIP systems can operate only in a closed mic environment. Closed mic operations require data communications to function. If data communications fail for any reason, radio systems and VoIP systems have Voice Fallback modes that allow operators to communicate directly with dispatch.
VoIP systems can also be configured to automatically include specified devices on all calls. This feature helps dispatchers because they do not need to remember to add, for example, Road Supervisors on all calls.