Installing Multiple Telephones On a Single ADSL Line


Incoherent Poster
Aug 14, 2011
Gurgaon | Mumbai
Since this question seems to be asked a lot these days, I'll use this post to explain how one can install multiple phones on a single ADSL line without affecting the performance of the connection.

Now, depending on your internal wiring, you can have either of the following two setups :-

Setup 1

As can be seen from the figure, splitting the main line that enters your place using a SPLITTER effectively divides it into two components - the ADSL component that feeds the modem and the phone component that feeds the telephone circuitry of your place. Since, the telephone circuitry is isolated from the adsl component, there is no interference between the two, and both devices work flawlessly.

Setup 2

However at many places, it isn't possible to split the main. It is in such setups that people often complain, after installing an adsl modem in one of the rooms, they hear disturbance in the telephones installed in the other rooms, this is because of interference between the adsl and analogue phone line components. In such scenarios, installing a line FILTER before each telephone, filters out the adsl component, and retains only the analogue component, thereby solving the issue of disturbance in the line. The line filter also prevents the telephone component from affecting the adsl modem.

Hope this clears up doubts people have regarding using multiple phones on a single line !
  • Like
Reactions: gopichandpai