Every type of communication, natural or man made, comes in two basic forms: synchronous or asynchronous.
Synchronous communication means that for each message, the sender expects to get a reply from the receiver, like a telephone call. There is a back-and-forth exchange, so that each party knows that the other is receiving the message. If there is no response, you can be pretty sure that communication didn't occur.
Asynchronous communication means that a message gets sent but the receiver is not expected to reply, like a radio broadcast or a newspaper.
Each of these communication types has its own value and purpose in data communications, and the DataHub program is capable of both. The specific circumstances and application will determine which form of communication you end up using.