Overview
Repeaters operate at the Physical Layer (Layer 1). They are used to overcome signal attenuation (weakening) that occurs as a signal travels through a medium like copper or fiber.
How it Works
A repeater does not understand the data it is carrying; it simply amplifies or regenerates the physical signal (bits). In digital networking, it regenerates the signal to remove noise and distortion.
Modern Context
While standalone repeaters are less common today, the repeating function is built into many other devices, such as switches, routers, and wireless range extenders.