The Dialogic D/120 JCT card has 12 lines arranged in 6, RJ-14(two-line) jacks. If you do not have RJ-14 cables, you can use the splitters that come with the Dialer in the orientation below.
This example shows a card with 4 jacks but you would do the same thing with the D/120 JCT card that has 6 jacks. The first 2 lines are at the top of the bracket, closest to where the screw would hold the card into the case. Then the second jack would be lines 3 & 4, the 3rd jack is lines 5 & 6 and so on.