As mentioned in my recently published blog article, I would like to explain to you the small but subtle differences between the two INDUSTRONIC functions Parallel Group and MultiControl Group.
You may remember that both functions enable the communication with a group of members. At the beginning of the communication when one subscriber speaks to the group it is always a point-to-multipoint connection where all members of the group can listen to the message simultaneously. As soon as one member of the group answers a point-to-point connection is established. This is the same for both functions. Let´s have a look at the differences.
Difference No. 1
The first small but subtle difference is that within a parallel group all other members are indicated as busy as long as one member speaks. Whereas the members of a MultiControl group are free for other calls.
Difference No. 2
The second difference becomes obvious when the subscriber answers again. When answering the parallel group the point-to-point connection changes back to a point-to-multipoint connection. Again all members of the parallel group can listen to the message.
For the MultiControl group the point-to-point connection remains established, which means that the other group members cannot listen to the conversation.
A typical application example for a parallel group is the installation of two intercom stations at two different places in a plant which are favorable for the operator, e.g. at the beginning and at the end of a long rolling mill train. Depending on the place of installation, the operator can decide at which intercom station he wants to answer a call.
A MultiControl group can be used in a centralized, multifunctional control room. If one of the intercom stations is already busy, another free intercom station can accept a different call.
See also my previous articles about two-way communication.