Universal routers combine standard routing functions with universal compatibility, allowing them to manage traffic between networks and share an internet connection among multiple devices. They are particularly versatile because they can connect to different types of internet sources, like a specific provider's 4G/5G network or a wired connection, making them suitable for home, office, or travel. Key functions include directing data packets, creating a Wi-Fi hotspot, supporting multiple devices, and providing both wired (LAN) and wireless (WAN) connectivity.