Split the dsl filtered line on to line 1 and feed the unfiltered to
line 2.

The telephone company has already installed a DSL-splitter that splits
one incoming phone line into a line for DSL and another line for all
the analog phones. Then I don't need to use filter on those analog
phones. Is this what you are referring to?

Then pop down to radio shack for a line1/2 splitter and keep that
with
your DSL modem.

Is it like an one-to-two adapter that we can use to plug the DSL modem
in one jack and a regular phone in another jack in the adapter? In
where I am going to put my computer, I have already had a phone jack
for DSL and another phone jack for analog phone; therefore, I don't
need an one-to-two adapter. However, if I later on decide to move my
computer elsewhere, I may need that adapter because I only have one
phone jack in all the other locations in my house. Thanks for pointing
this out.

Of course, If you already have 2 land lines, this obviously will not
work.

I only have one land line (with 2 physical wires inside the cable).
Therefore, this will apply if I decide to move my computer to a
different location.

Jay Chan