Which device connects different networks and directs data between them?

A router connects two or more separate networks and decides the best path for data packets to travel between them. When your home network needs to reach a website hosted on a server across the world, it's the router that reads the destination IP address on each packet and forwards it to the next network hop until it arrives.

Here's how it differs from the other three options:

An access point extends a single network wirelessly. It doesn't connect different networks together - it just lets Wi-Fi devices join an existing LAN. Think of it as a door into one room, not a bridge between buildings.

A switch operates within one network. It connects multiple devices (PCs, printers, cameras) on the same local network and uses MAC addresses to send frames to the right port. A 24-port Gigabit switch in an office, for example, lets all the desktops talk to each other and to the local file server. But it won't route traffic to a different network on its own.

A firewall inspects and filters traffic based on security rules. It decides what's allowed in or out, but its primary job is protection, not routing. Some firewalls do include routing capabilities (Fortinet's FortiGate series, for instance), but that's a secondary function.

What makes a router unique is that it works at Layer 3 (the Network layer) of the OSI model, meaning it reads IP addresses and makes forwarding decisions across network boundaries. Switches work at Layer 2 (Data Link), using MAC addresses within a single broadcast domain. That's the fundamental distinction.

In practice, most home routers today combine all four functions - routing, switching, wireless access point, and basic firewall - into one box. But which device specifically connects different networks and directs data between them, the answer is always the router.