the dp plus lnb supports only dp lnb's for the input,
a legacy twin and a legacy dual could be combined with a sw21 switch or the 4x1
diseqc switch (these come with most stb's)
dish makes a dp 21 or dp 34 switch which will work with a dp twin or quad and a dp single/dual
legacy lnbs are compatible with d_tv lnbs as well,
and will work with diseqc 4x1 switch
dpp lnbs use mhz range 950 to 1450 for odd and even transponders
and a second full signal from 1650-2150 for odd and even.
they are primarily used for dn dual tunners using a single cable penetration.
the dp lnbs use 950-1450 odd transponders only
and 1650-2150 even transponders only.
The input of the dpp lnb can "upconvert" the dp dual to the full set of signals in oth mhz ranges and pass them all in one cable.
The dpp does have 2 out ports...
the legacy lnbs use only the lower mhz rqange 950-1450 odd and even.
when any lnb is connected to an external switch, the internal switch gets put in default mode, each port send a single sat signal to be combined by the external switch.
a dp twin hitting 110,119 have both sat signals coming out both ports.
when you use a
dp34 switch, the 1st port has only 119
the second port has only 110.
if you use a diseqc 4x1 switch you need legacy lnbs and they combine the signals of up to 4 sats.
Hope this helps.