The D-Link DSL-16MF Microfilter separates the analogue voice-frequency signals from the DSL (Broadband) data signals. If microfilters are not used, the DSL data signals are heard as 'noise' on any equipment connected to the telephone line | Apart from being disruptive during a telephone conversation, there is the possibility that the additional DSL signals may cause interference with alarm units that may be connected across the line | High quality, low pass filter with optimum performance | Works with both VDSL2 and ADSL2+ enabled telephone lines | Compliant to all local standards | Ensures a clean DSL connection | A Filter is required for each phone device connected to your wall outlet (Phone, Fax, Analog Modem, Answering Machine, Alarm Dialler 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