Mysteries of the Broadband Router Explained

If you’re reading this then you’re connected to the internet, and the chances are that connection will be through a broadband router. But what is a “broadband router”, and what does it do ?

There are two types of broadband routers, depending on if your connection is via a standard telephone line or a cable service (e.g. Virgin). Most UK users connect to the internet through a telephone line so we’ll look at that first.

A broadband enabled telephone line is known as a DSL line – Digital Subscriber Line. “Subscriber Line” just means it’s a telephone line that you subscribe to (rent, or hire) and “Digital” means that it can carry data as well as voice. Most domestic lines are actually ADSL – Asymmetric DSL. “Asymmetric” because they are slower at uploading data (from you to the web) than they are at downloading data (from the web to you). Since most people download much more than they upload, this isn’t a problem and is a convenient way of squeezing more capacity into the telephone network.

A DSL Broadband Router then is actually three devices in one little box. It’s a modem, a network switch, and a WiFi transmitter/receiver. These three sections can be seen at the rear of a typical router -

A standard telephone line is designed to carry audio signals – your voice – therefore in order to send data the data must be in a suitable audio form. The modem takes data and turns it into “audio tones” that can be carried on the telephone line.

A network switch allows you to connect computers together, via cables, to create a network. This network is local to the where the switch is placed, therefore it is known as a Local Area Network, or LAN. A standard router normally has 4 LAN connections on the rear , printer, or other network device using a suitable able.

The great thing about a network switch is that you can expand a LAN by connecting another network switch to one of the connectors, and then another switch to the second switch, and so on. This allows you to build up a large network using simple components. All computers attached to the switch can be setup to “see” and pass data to each other, and internally the router allows all connected devices access to the modem and then on to the internet.

The WiFi transmitter/receiver allows WiFi devices, such as laptops or smart phones, to connect to the router. Once a WiFi connection is made the router allows access to anything connected to the switch (so that a WiFi device can become part of the LAN) and also to the modem and thus the internet.

The front panel of the router will have status lights. These lights are usually similar to those shown and have the following meaning when they are on

Power - the router is powered up ok

1-4 - a device is attached to one of the 4 LAN switch ports (light flashes)

DSL - the phone line is connected and working correctly

Internet - the internet service is working correctly - this is often shown as a "world" icon

WiFi - the WiFi is switched on and working