The DSL filters basic job is to filter out noise so your DSL will connect and allow you to have internet. There are many types of DSL filters for many different situations.
For a single line phone all you would need is a standard single line filter. Such as
For hanging a phone on the wall
For a single line ANSI Certified Filter use
DSL filters are regulated to make sure they can filter up to 5 telephone devices on your telephone system. If you have more than 5 telephone devices on your 1 or 2 line telephone system then you will need a dynamic filter, such as a
If you need a dynamic filter but want it to be meet ANSI specifications you will need a
For a standard 2 Line telephone then you will need
For a wall mounted 2 Line phone you would need a 2 Line wall mount filter then we have a
If you need a kit of DSL Filters a standard kit is the
For a Kit with an extra Unfiltered jack we have a
For a 2 line kit with Dynamic Filters we have a
If you have an Alarm System on your line you may need a Alarm Panel Filter
Before I can explain how a DSL filter works I have to explain how a Customer Premise Equipment (CPE) Phone system works. Like any good documentary let's start at the source.
The Telephone Network Interface Device (NID)
There are many NIDs out in this great world, but we will talk about the most common one. The NID pictured has 2 Lines on it. When DSL is install the customer is told that they can only put DSL on Line 1.
The Purpose for this is that 99% of all DSL modems are wired to work on the Primary Pair. Well what does that mean? The red and green wires are the only ones activated on a DSL modem.
So why are there 1 and 2 Line DSL filters? When you get a 1 line DSL filter is only has the primary pair inside. Which means you would loose line 2. When you get a 2 line filter then both the red and green and the black and yellow are active and filtered, just incase you have your DSL on line 2 and you have a Line Swapper at your DSL modem to adjust things. As you can see a Line Swapper basically changes the wire location so that the primary pair are in the seconadary position and the secondary pair are in the primary position.
What is a ANSI Filter? ANSI stands for the American National Standards Institute. If a filter is ANSI certified then it has been approved to perform at a certain level of excellence. How does a NID splitter fit in to all of this? A NID splitter is a big filter that filters the entire CPE phone system. It basiclly goes between the Telco and the Customer side of the NID. This is a basic drawing of how it would wire in a NID.