A DSL filter is an analog device that improves a DSL connection by minimizing telephone signal interference with the DSL system. When installed, it acts as a barrier to prevent low frequency telephone signals to interfere with the high frequency ADSL system and vice versa.
How DSL Filters Work
Telephone signals usually range from 300 to 3400 hertz, while ADSL systems use frequencies between 25 KHz and 1.1 MHz to carry fast data traffic. Both signals are present and they pass through the same copper wire. With both signals working at the same time in the same line, interference is possible causing problems for ADSL (low speed) and telephone (line noise) connections.
A DSL filter is usually just a small plastic box with a plug which goes to your phone socket. It has two outputs, one for your DSL modem and another for the telephone. By filtering and sending the right frequencies to the appropriate sockets, a DSL filter reduces interference problems. It also maximizes the 1.1 MHz frequency capacity of the copper line by attenuating the tendencies of the two signals interfering with each other.
Installing DSL filters does not require a technician's help. More often than not, most companies send the micro-filters with the DSL modem directly to the end user. To install a DSL filter, you have to take the steps listed below.
- Plug your phone and modem into the RJ11 jack.
- Switch on the DSL modem and see if your computer will connect to the Internet.
- Check your phone for a dial tone.
The methods for installing more than one DSL filter are listed below:
- Unplug other phones in your house before installing the DSL filters.
- Immediately check for a dial tone on each phone after installing the filters.