How to Build a DSL Filter

DSL Filter Schematic

DSL data connections are carried on the same phone lines as voice communications but operate at non-overlapping frequencies. When data and voice are carried on the same phone line at the same time, however, data frequencies can attenuate and cause interference which affects the quality of voice communications for traditional telephones. In order to prevent this interference from occurring on your home phone, a DSL filter must be installed which stops the phone and data signals from interfering with each other.

Things You'll Need

• Two 6.8 mH inductors Two 10 mH inductors One 400V 0.022 uF capacitor One 400V 0.015 uF capacitor RJ-11 jack (female) RJ-11 plug (male) Circuit Board

Instructions

1. Mount the two 6.8 mH inductors on the circuit board going from left to right on the circuit board. The wall side of the filter will be on the left side of the circuit board. The inductors are mounted by pushing the wire through the board and twisting the end of the wire through the board. Next mount the two 10 mH inductors on the circuit board from the next terminal to the right from where you connected the 6.8 mH inductors and connect the other end of them to the next terminus to the right.

2. Connect the .022 capacitor on the circuit board in between the terminus of the first two 6.8 mH inductors. Capacitors are connected to the circuit board in the same manner as the Inductors by pushing the wire through the circuit board and twisting off once pushed through the board. Connect the .015 capacitor in the same manner at the terminus of the two 10 mH inductors.

3. Connect the RJ-11 male and female jacks to the circuit board on the left and right hand side of the board respectfully. The male and female jacks are connected in the same manner as the inductors and capacitors by twisting off the plugs connection to the circuit board.

4. Connect the phone line and home phone to the board and test to confirm a dial tone is audible.

Tips & Warnings

• Making your own DSL filters for the home will save you over 70% over the purchase price of the same filter at an electronics store.

Resources

• BroadBand Reports Tutorial on Making a DSL Filter
• Wall Mounted DSL Filter Information