Do DSL Modems Use Regular Phone Cords?

By Josienita Borlongan

Using splitters or microfilters ensures quality service for DSL and phone lines.
i Andy Sotiriou/Photodisc/Getty Images

A digital subscriber line, or DSL, uses the same copper path as an existing phone line to allow Internet connectivity while simultaneously using phone lines dedicated to incoming and outgoing calls. In most cases, the same phone lines connect to various automated machines, such as fax machines, answering machines and automated building or home alarm systems. The phone line and DSL service can utilize the same path simultaneously, provided you separate the two signals properly.

Utilizing Regular Phone Cords

DSL installations use regular phone cords; however, they may cause noise interruptions to phone devices, gadgets or systems connected to the phone line when used simultaneously. To prevent these noise interruptions, phone cords with DSL modem connections require DSL line filters or splitters.

How Does DSL Works on Regular Phone Cords?

A DSL modem allows computers to utilize the phone line to transfer digital data, considered high frequency, in the same manner by which a regular telephone makes outgoing voice calls, which are low frequency. Connecting the DSL modem to the phone jack on the wall outlet will enable the data connection. Subsequently, connecting the modem and the computer enables Internet connectivity. Installing microfilters or splitters is necessary when other devices use the same phone line simultaneously to prevent service interruptions or failures.

Using Microfilters on a Shared Line

Place RJ11 microfilters on each phone jack, except to the one directly connected to the DSL modem that connects to your regular phone cord. If you place filters on the phone cord that connects directly to the DSL modem, the latter will not work, stripping out the Internet signal from the phone to the modem. Microfilters are small, plug-in devices that filter high frequency noises associated with DSL Internet signals. You don't need a technician to install microfilters, because they do not require additional wire connections. Electronics shops often carry microfilters; however, in most cases, your DSL service provider or your phone company can provide one for you. Self-install modem kits, commonly labeled as "splitterless," already come with microfilters.

Using Splitters on a Shared Line

Using splitters is a common practice with asymmetric digital subscriber line, or ADSL, connections to filter the signal noises to phone voice services. Splitters split the line into two pairs to remove the DSL frequency noises from one of the lines. The DSL signal passes through a designated data jack, while over-the-phone discussion travels through the designated phone jack on the splitter. In most cases, the telephone company or service provider will install the splitters for you; however, you can also install one on your own. In some cases, you may install splitters in the interior premises of your home while a technician will install splitters outside, perhaps on a wall. Contact your service provider for advice on what type of splitter to use.

The Future

Newer versions of DSLs no longer require filters or splitters. These Internet connections do not emit signal frequency noises that affect regular phone service quality. These plug-and-play devices use a more enhanced digital technology over existing phone connections, and provide faster Internet connection speeds. In addition, POTS, or plain old telephone service, commonly referred to as landlines, may become outdated with the influx of VoIP, or voice-over Internet protocol. With the ever-changing world of technology, newer and faster means of connecting to the Internet will become more available to all Web users.