I have a client with a max'ed out Prostar DCS compact (4 lines, 8 ext.). Client wishes to add one more line.

What do I need to upgrade? There is an available SLI slot and an existing MISC2 card (and one 4COP card). It appears I have to add a sisterboard in order to add another 4COP? :confused:

To add a line,you will need to add an expansion board and then either a 2X4 SLI or 2X4 DLI card.
There is no other way to add a 5th line.

OK, thanks!

This system must be different to the one we had here

The compact exp board we have has 3 universal slots, in which you could put a 6dli, 6sli, 4trk, 4bri or AA card.

Correct,
The expansion board here has 3 slots but only takes the 2X4 cards or a SVMi4 series card.Samsung has different cards/parts for different world markets.