📞Wireselectrical signals through copper (old phones)

📻Radio wavesthrough the air: radio, TV, phones, Wi-Fi

💡Fibre opticspulses of light in glass threads; very fast internet

🛰️Satellitesrelay signals around Earth’s curve

📶Cell towerspass your phone’s signal along

🔵Bluetoothshort-range radio for earbuds and speakers