ADSL filter simulation

[yAro]

I'm trying to simulate an ADSL filter in Multisim.
I got all the components as they were connected in
a real filter
but there some things I don't understand and I
must add that I'm quite new to electronics.

The filter's PCB has 2 pins for Line-in, 2 for
ADSL-out and 3 for the phone-out (UK phone), where
2 of them
are just connected in parallel to a capacitor. Why
there a 3 on the phone output not 2 like on the
Line input?

I noticed that the ADSL socket is directly
connected to the Line so as it should be all the
signal from the Line
goes straight to ADSL modem or router. On the
other hand signal coming out from the Phone socket
passes through
the filter, where all the high frequencies are
attenuated. The problem is now how to represent
all these sockets in
Multisim? Would resistors do? If yes, then what
values should they have?

Then if I want to connect a Bode Plotter to the
circuit it needs an AC source. Where to connect
it?
Should it be connected to the Line? What voltage
and frequency should it have?
Any help would be greatly appreciated
yaro