How do I set up my DSL Filters?

DSL Filters, or Microfilters as they are often described, are required to separate the normal low-end frequencies associated with voice calls from the high-end frequencies used by your ADSL connection. The correct installation of these filters is important to ensure the best possible performance of your ADSL connection.

Introducing the DSL Filter:

The diagram below illustrates one example of an ADSL Filter. There are several different varieties - including the dongle-type below, a splitter which plugs directly into your wall socket, and a plate which replaces the standard BT Master Socket.

The illustration below shows what each of the connectors are for:

Installing your DSL Filters:

You should remember the following basic rules when installing your DSL Filters:

Every telephony device (Telephones, Faxes and Sky Digital Boxes) must pass through a DSL Filter.

No device should pass through more than one DSL Filter.

For the most basic setup of your ADSL hardware, with just one BT Telephone socket running one Telephone and your ADSL Router/Modem, all you require is the one DSL Filter. This should be plugged directly into the BT Master Socket, then a Telephone and ADSL Router/Modem can be plugged in to the appropriate connectors.

The majority of Master sockets will look like the socket shown below:

If you have more than one telephony device you wish to use, and have more than one BT wall socket, then each wall socket will require a DSL Filter. Wherever possible you should connect your ADSL router/modem to the DSL Filter which is connected to your Master socket.  This will ensure the best possible connection speed and reduce the chance of stability problems occurring. 

NOTE: If your computer is located in a different room to your Master socket we would advise purchasing a Wireless router and Wireless adapters for your computer - with 802.11g support - so the ADSL router may still be connected to the DSL Filter connected to your Master socket, with the minimum possible wiring.

If you have only the one BT wall socket then a similar setup to the one shown below may be used:

As you can see from the diagram, a standard splitter is in use along with an extension cable to allow the use of other telephones or fax machines.

If you have a BT extension socket you may be able set up your equipment as shown in the diagram below:

The diagram above shows how to utilise a BT Extension socket for use with a fax machine and/or digi-box.

NOTE: It is highly recommended that you begin by working from the BT Master socket to your telephony devices and ADSL router.

If a device passes through more than one DSL filter then that device will not be useable.