DSL filters remove line interference when telephones share DSL service lines. They are required for some configurations and separate voice and data signals. Split DSL configurations do not require filters, but splitterless configurations do. DSL has advantages over dial-up service. Other equipment may have built-in filters, and signal clarity issues can be caused by faulty filters or damaged hardware.
Digital Subscriber Line (DSL) filters, also known as microfilters, are small in-line devices sometimes required for DSL installations. They filter out line interference to standard telephone equipment when the telephones share the same DSL service lines. Not all configurations require the use of a DSL filter, although they are often required for every telephone connection.
Basic designs
A DSL filter is a small rectangular device with telephone connections on both ends. The person installing a DSL system simply unplugs a phone line from a wall jack, plugs the filter into the wall connection, and then plugs the phone line into the filter. Fax lines and answering machines also tend to require DSL filters. The filters separate the voice and data signals sent over the telephone lines, ensuring that neither interferes with the other.
Split DSL configurations
There are two methods for installing DSL service: split or splitterless. You don’t need a DSL filter if you are using the split method. In this case a technician visits the premises and installs a splitter in the main telephone line. Two lines emerge from the splitter; one line feeds into standard telephone jacks, while the other line is used exclusively for a DSL modem. In this case a DSL filter is not needed because the splitter has separated the voice and data signals.
Splitterless configurations that require filters
The second method, which has gained popularity because it does not require a technician, can be installed by the user. In this case, the end user can configure a DSL modem together with several microfilters. DSL service is sent over the main service line, so the end user just needs to plug the modem into any existing telephone wall jack. However, the signal reaches all connected telephone jacks, creating possible leakage noise on telephone, answering machine and fax lines. A DSL filter attached to each of these lines blocks interference that could be created by the service.
Advantages of DSL configurations
DSL has three big advantages over dial-up service: it’s always on, it’s up to 50 times faster, and it doesn’t hog your phone line, even if you’re using the same connection. Standard telephone equipment uses an analog signal, while DSL communicates on a higher digital frequency. This allows a user to browse the Internet using DSL service, while simultaneously talking on the phone.
Other filters and troubleshooting
A DSL filter is typically a small device, although some other equipment may have built-in filters. Some surge protectors or power strips, for example, include a filter to help with DSL connections and to protect equipment in the event of a surge across a telephone line. Problems that arise with signal clarity can be related to faulty or improper filters, although faults in telephone cables or damaged hardware can also lead to poor performance.
Protect your devices with Threat Protection by NordVPN
