Final answer:
A hub is the device that regenerates a signal and broadcasts it to every connected computer. Unlike switches or routers, it doesn't filter or direct traffic specifically. Firewalls are for security, not signal broadcasting.
Step-by-step explanation:
The device that regenerates a signal and broadcasts it to every computer connected to it is known as a hub. A hub operates at the physical layer of the OSI model, which means it does not filter traffic or perform any data processing functions other than signal regeneration. Unlike switches, which can direct data to a specific device, or routers, which route traffic between different networks, a hub simply repeats the incoming electric signals to all of its ports, thereby broadcasting the data to all connected devices. Firewalls, on the other hand, are security devices that monitor and control incoming and outgoing network traffic.