Separating the DSL signal from the telephone service requires either a splitter in or near the NID or filters at each telephone device. Ideally, the DSL service provider will install a DSL splitter module inside the NID or in a separate enclosure next to the NID and run a new cable to the DSL modem location. But many service providers will avoid the cost of sending a technician to install a splitter and instead will provide filters as part of a “self installation kit.” In addition to the DSL modem or router and the cables to connect it to the line and to your computer or LAN, these kits include a few filters (also known as “microfilters”) for your phones. The kit may also include a few duplex adapters to so that you can use one jack for both the DSL connection and a voice connection or one filter for several voice connections. Of course, there will probably be an additional charge for the filters and adapters.