In my last two blog articles I described different ways of bidirectional communication. This time I would like to give you an insight into a unidirectional communication method where a call is established to a pre-defined group of members – the group call.
One Subscriber Speaks – the Others Listen
For a group call, one subscriber speaks and all group members listen to the message simultaneously (Point-to-Multipoint connection). The individual groups can be configured depending on project and customer-specific requirements.
In complex industrial plants often many different group calls are defined which address individual areas or buildings (e.g. factory building, warehouse, etc.). For example, if faults occur in the course of a process, the employees in the corresponding areas can be informed by an announcement.
The operator at Station A presses the key configured with the desired group as target, keeps it pressed and speaks into the microphone (Push-to-Talk). All members contained in the group listen to the announcement simultaneously.
The following illustration shows the communication procedure.
You can also assign an individual priority for each group call. This means that an active group call overrides functions with a lower priority. A group call can only be interrupted by a voice connection or function with a higher priority.
Pre-tones and Warning Beacons
It is possible to play back a pre-announcement tone prior to a group call or the actual message. A positive effect is that listeners stop their conversations or noisy activities to focus on the announcement that follows.
Furthermore, there is the option to activate flashing warning beacons which indicate the call visually.
Download a more detailed version of this blog article as PDF here.