What type of electrical interference can be caused by computer network equipment?

Computer network equipment, such as Ethernet switches and routers, relies on high-speed digital clocks and data streams to function. These fast digital transitions create rich harmonics that extend well into the radio frequency spectrum, often radiating from unshielded network cables acting as unintended antennas. Because the internal clocks can drift slightly and data traffic fluctuates, the resulting radio frequency interference (RFI) typically manifests as unstable signals. You will often hear these as unmodulated carriers (birdies) or strangely modulated signals that appear at regular frequency intervals across a band. Other options describe different RFI sources. An AC hum is generally caused by power supply ground loops or failures, a slow clicking noise often originates from electric fences or thermostat relays, and a pulsing whine is typical of switching power supplies or motors starting up.