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DSL


Digital subscriber line (DSL) is quickly replacing traditional modem access because it offers higher data rates for a reasonable cost. In addition, you can make regular phone calls while online. DSL uses higher frequencies (above 3200Hz) than regular voice phone calls use, which provides greater bandwidth (up to several megabits per second) than regular POTS modems. DSL “modems” are the devices that allow the network signals to pass over phone lines at these higher frequencies.


Most often, when you sign up for DSL service, the company you sign up with will send you a DSL modem for free or for a very low cost. This modem is usually an external modem (although internal DSL modems are available), and it usually has both a phone line and an Ethernet connection. You must connect the phone line to the wall and the Ethernet connection to your computer (you must have an Ethernet NIC in your computer in order to connect to the DSL modem).


If you have DSL service on the same phone line you use to make voice calls, you must install DSL filters on all the phone jacks where you have a phone. Otherwise, you will hear a very annoying hissing noise (the DSL signals) on your voice calls.

Cable


Another high-speed Internet access technology that is seeing widespread use is cable modem access. Cable modems connect an individual PC or network to the Internet using your cable television cable. The cable TV companies use their existing cable infrastructure to deliver data services on unused frequency bands.


The cable modem itself is a fairly simple device. It has a standard coax connector on the back as well as an Ethernet port. You can connect one PC to a cable modem (the PC will need to have an Ethernet NIC installed), or you can connect the modem to multiple PCs on a network (using a hub or switch).

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