A repeater is a network device that operates at the physical layer of the OSI model¹. Its job is to regenerate the signal over the same network before the signal becomes too weak or corrupted to extend the length to which the signal can be transmitted over the same network¹.

The physical layer is the lowest layer of the OSI model. It provides mechanical, electrical, and other functional aids to enable, maintain, and transmit bits about physical connections³. It also defines the specifications of certain transmission media, such as copper cable, fiber optic cable, or wireless networks³.

A repeater is a simple device that does not perform any filtering or processing of the data. It just amplifies and retransmits the signal as it is. A repeater can be used to connect two segments of a network that use the same protocol and media type².

Here is an example of using a repeater to extend the range of a wireless network:

The repeater receives the signal from the wireless router and retransmits it with higher power, so that the wireless device can receive it. The repeater does not change the frequency or format of the signal. It just acts as a relay between the router and the device.