USB to RS232 Hub Manufacturers tell you that the main function of the hub is to regenerate, shape and amplify the received signal to expand the transmission distance of the network, and at the same time concentrate all nodes on the node centered on it. It works on the first layer of the OSI (Open Systems Interconnection Reference Model) reference model, the "physical layer".

USB to RS232 Hub Manufacturers tell you that the hub is the same as the network card, network cable, and other transmission media, it belongs to the basic equipment in the local area network, and adopts the CSMA/CD (Carrier Sense Multiple Access Technology with Collision Detection) medium access control mechanism.
USB to RS232 Hub Manufacturers tell you that a hub is a pure hardware network bottom device and basically does not have the "smart memory" capability and "learning" capability similar to a switch. When it sends data, it is not targeted, but is sent by broadcasting. That is to say, when it wants to send data to a node, it does not directly send the data to the destination node, but sends the data packet to all nodes connected to the hub.
USB to RS232 Hub Manufacturers tell you that HUB is a multi-port repeater. When the HUB is used as the central device, a fault occurs in one line in the network, which does not affect the work of other lines. Therefore, HUB has been widely used in the local area networks. Most of the time it is used in star and tree network topologies, with RJ45 interfaces connected to each host (also BNC interfaces).
The above is the USB to RS232 Hub manufacturer's introduction and analysis of the hub, hope it helps you.