Dsl filters are micro filters that filter any phone line interference from dsl data communications, when dsl and phone service are both being used simultaneously on one analog line. If a dsl modem is installed with a dsl splitter than the filter is not needed, but if a splitter isn’t used then the dsl line filter is a must to have.
Dsl modems runs at a higher frequency and the phone line runs at a lower frequency, the dsl inline filters allow the modem to run from one port and the phone line from another port. Any other devices such as a fax machine would also have to have a dsl splitter filter to prevent any interference from the dsl data frequencies. Without the dsl phone filters, these devices would receive too much interference from the signals and wouldn’t be able to function properly.
Dsl phone filters do have their disadvantages though. They don’t always filter out the noise from the dsl frequencies and they have been reported to cause the phone from not ringing when receiving a phone call. Dsl filters also have been known not to work with some devices, such as monitored alarm systems and the special devices for telephones that the hearing impaired use. In those cases, they would have to have their own phone lines. That is not always the case though.
Some alarm systems can work with the same line as the dsl; with the use of an alarm system dsl filter. There are some special wall phone jack dsl filters designed for some security systems, so check with your isp provider for what they have available.
For those who are having a new home or office built, and you plan on having dsl connections at various points in the house, decide the spots where they will go. A dsl filter schematic can be drawn up of the dsl filtered structured wiring and there won’t be any questions of where to place the dsl filter wall mounts.
If you’re install a phone line into your office to have a pc and dsl modem installed, consider using a dsl filter module. This allows for the phone and dsl to run on the same line by separating the signals only you wouldn’t have to use a regular dsl filter. It would be installed with the phone jack and there would just be 2 ports to connect your phone and your dsl line into. This would eliminate the need for the bulky dsl filter sticking out of the phone jack. While you’re at it, it might be a good idea to have a station protector for dsl filters installed as well. It will protect the phone line from any surges that may occur.
If you’re experiencing static noises within your phone line with your dsl modem, contact your local phone company as they can use dsl measurement filters to test the line and determine the rate of noise occurring in the phone line because of the frequencies caused by the dsl filter.
When looking for the dsl filters that fit your needs, consider talking to your local phone company to see what they have to offer. If not, the web is a huge resource for websites that sell good quality dsl filters at good prices. Check out each site’s selection of the various types of dsl filters and make sure that they’re compatible with your phone lines and dsl modem.