The alternative is PCD7100 not PMA-7100, sorry for the mistake.
Denis

Our alternative to the Sigtronics is the PMA-7100, but we would have to
remove an AM/FM cassette entertainement center to put the
PMA-7100 at the place.

The PMA-7100 is a very good intercom with all the features you
discribed for the intercom, but I thing that the behavior
of the CD input and audio #2 input lack of possibilities, audio #2 can
be used only in crew mode, it's not possible to select between CD
and input #2 internaly or externaly with a switch, for a unit of this
class it's is a pity.

If the SCI-S6 is a good unit (that's what I would like to be sure),
we would conserve our stereo center and have all the flexibility with
music audio inputs.

Denis Rochat