DSL Modem - Description

Description

A DSL router consists of a box which has an RJ11 jack to plug a standard local phone line into. It has several RJ45 jacks to plug Ethernet cables to connect it to local computers or printers, creating a local network. It usually also has a USB jack which can be used to connect to computers via a USB cable, to allow connection to computers without an Ethernet port. A wireless DSL router also has antennas to allow it to act as a wireless access point, so computers can connect to it forming a wireless network. Power is usually supplied by a cord from a wall wart transformer.

It usually has a series of LED status lights which show the status of parts of the DSL communications link:

• Power light - indicates that the modem is turned on and has power.
• Ethernet lights - There is usually a light over each Ethernet jack. A steady (or sometimes flashing) light indicates that the Ethernet link to that computer or device is functioning
• DSL light - a steady light indicates that the modem has established contact with the equipment in the local telephone exchange (DSLAM) so the DSL link over the telephone line is functioning
• Internet light - a steady light indicates that the IP address and DHCP protocol are initialized and working, so the system is connected to the Internet
• Wireless light - only in wireless DSL modems, this indicates that the wireless network is initialized and working

The DSL router is designed to be installed by the customer. Usually it comes with a CD or DVD containing an installation program, which when inserted in the computer gives graphical step-by-step instructions for connection. Once the cables are connected and the modem is powered up, the program activates the DSL service by asking for a PIN . From then on the internet link is active whenever the router is turned on; no telephone call is necessary to connect. When turning on the router it takes several minutes for the local network and DSL link to initialize, usually indicated by the status lights turning green.

The router has its own web page, which can be accessed over the local network. It will display the status of the DSL and network connections, and can be used to change many router settings such as the firewall parameters. It usually has the IP address http://192.168.1.1/. To log in to the router and change settings a username and password are required. Some early routers came from the manufacturer with the same default username and password programmed in to every unit, usually "username" and "password". This is a serious security hole, particularly with wireless routers, and the defaults should be changed.