Routers and modems are two of the most common computer peripherals, yet many people don’t know the function of each one. While the two devices may look similar, they each serve a difference purpose. Fortunately, the functions of the two devices are pretty easy to understand.
A modem is a device that provides access to the Internet.
The modem connects to your ISP, which typically provides either cable or DSL Internet service. Cable modems have a coaxial (or “coax”) connection, which is the same type of connector found on a TV or cable box. This connects to a cable port on the wall. DSL modems have a telephone connector, also called an RJ-11 jack, which connects to a telephone socket on the wall.
By connecting your modem to your router (instead of directly to a computer), all devices connected to the router can access the modem, and therefore, the Internet. The router provides a local IP address to each connected device, but they will all have the same external IP address, which is assigned by your ISP.
To summarize, the device connection order is outlined below:
PC or wireless device.