X10 Filter

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X10 was developed in 1975 and it is starting to show its age.

Household electrical wiring (the same which powers lights and appliances) is used to send digital data between X10 devices. This digital data is encoded onto a 120 kHz carrier which is transmitted as bursts during the relatively quiet zero crossings of the 50 or 60 Hz AC alternating current waveform. One bit is transmitted at each zero crossing. (wikipedia)

The problem is that X10 is susceptible to interference in its passband. Modern lighting and AC/DC converters often create noise onto the power line in the X10 passband.

Inserting a filter between the source of the interference and the X10 device removes the problem.

Commercial Filter Parts

  • XPPF Commercial X10 Filter, wall wart style, not good for embedding inside house wiring, $24.99
  • PZZ01 Filter to eliminate X10 signals coming into the home from outside the home, $49.99
  • XPF-20A Wired in filter $49.00
  • XPNR Noise Reducer, does not require a connection to neutral line, $29.99
  • XPCR Coupler Repeater Amplifier, not a filter, per se, but might help in some cases, $59.99
  • Leviton 6287 Noise Block - no longer available


This card has the following features:

  • X10 interference filter
  • Notch filter
  • 120KHz center filter


The design is a T filter based on an estimate of the contents of the Leviton filter as described here.

Selected 8 uH instead of 7 uH inductors to get 120 KHz center frequencies.





LED light interference

  • Filters out interference created from LED lights
  • Install between the LED lights and the X10 switch

Wall wart/laptop AC adapter interference

  • Filters out interference created from DC switching power supplies
  • Install between the DC power supplies and the AC outlet

Card Installed in Box

  • Installed in the bottom of a deep light switch box
  • Use with X10 wall switch - WS467