Block the high frequency signals that emanates from any DSL service

Central Filter or Spliter

The DSL-12MF is a Central Filter (or Splitter) and is used on a line or extension where both an ADSL modem as well as a PSTN device is desired. The unit splits the line, providing a pass-through connection with no filtering to the ADSL modem, while providing a filtered connection to the PSTN device. Note that all other extensions still need to have a filter of some kind placed on them

A Filter is required for each phone device connected to your wall outlet (Phone, Fax, Analog Modem, Answering Machine, Alarm Dialer etc).
A maximum of 3 filters may be installed on any one phone line.
Not to be used in conjunction with a "back to base" security alarm system.