Voice Dispatching

Audio dispatch functionality is realized in BIRCS with a combination of two application modules, namely Radio Remote Control (RRC) and Audio Dispatch (AD). Radio Remote Control is a program to control the functions of a PC connected radio (usually at the base station) locally or over the network. Due to its multiuser capabilities it allows the setup of several dispatcher workstations accessing one single radio. Audio Dispatch (AD) streams the audio received by the radio into the network. It also converts an audio stream from the network into transmit audio for the radio when transmitting. For AD to work a soundcard interface connected to the PC and to the radio is required. Receive and transmit audio streams are visualized using colors in a bar graph spectrum display (0 to 3 kHz). By using AD every PC in the network is able to access the radio connected to the radio server PC for reception and transmission without any additional peripherals except the microphone and speakers of the PC. AD also maintains a network interface to RRC for transmit/receive switching. Depending on the network configuration AD is able to play the audio of other participants in the network so a dispatcher not only hears traffic received by the radio but also transmit audio coming from the other dispatcher workstations. AD can be configured to record the complete audio stream (inbound and outbound) into files, a function required by law in certain applications. As an additional feature AD can be used for local intercom purposes between dispatcher workstations over the network if configured accordingly. In conjunction with selective call messaging in analog (FM) systems AD can mute the audio stream from the network on user request and enable it again automatically on reception of a suitable (configurable) selective call code from the radio. So a dispatcher will only hear traffic directed to him and nothing else.

The following functionality is available in RRC/AD: 

·         Connect/disconnect to/from the radio

·         Display of version information (firmware and options)

·         Volume setting

·         Display brightness setting

·         Zone selection

·         Clarifier function (if applicable)

·         Channel selection within the selected zone and display of the channel parameters

·         Power level setting (high/low)

·         Transmit/receive switching (PTT)

·         PTT using a mechanical switch connected to a serial (RS-232) interface for convenience

·         Activation/deactivation of the monitor function

·         Activation/deactivation of the scan function

·         Nuisance deletion (while scanning)

·         Additional functions based on the underlying radio driver used for a given radio platform

·         Emergency handling (button triggered or triggered by LoneWorker or Man Down functions)

·         Radio power-off 

·         Spectrum display

RRC offers a UDP interface for third party applications to control some functions, for example such an application can trigger the transmission of pre-recorded audio messages on-air. Additional functions can be implemented if they are supported by the radio platform. Audio Dispatch is intended to run on the radio server PC and simultaneously on any number of dispatcher workplaces.

RRC and AD work with mobile (or even handheld) transceivers as control station radios. For direct access to a repeater a special version of these two application modules exist: RRC/R and AD/R (presently for Hytera branded repeaters only). In this case audio streams are digitally exchanged between the PC and the repeater over the network using the Real Time Protocol (RTP).