We have a DS1000 with the expansion card and 4 lines originally. There are 2 other lines which originally went to analog devices. We decided to move these 2 lines onto the DS1000 and use analog extensions for the devices instead. I connected the lines to the DS1000's 5th & 6th trunk ports then programmed the same as the other 4 trunks. (via Use Program 1001, 1002 & 1003) The new lines are not ringing into the DS1000 and when I access the trunks, instead of a dial tone I get a busy signal. (The lines work fine if I attach a single line phone directly.)

What did I miss on programming the new trunks or what's the proper procedure to add a new line on the DS1000?

Thanks in advance.

Check 1803 (trunk access), 1805 (ring assignment).
1701 (function key)

Check the cable/cord at the KSU for trunks 4, 5, 6. It should be a 6-pin modular plug with 3-pair cable/cord. Line 4 wires to pins 3 & 4 of the modular plug, line 5 wires to pins 2 & 5, line 6 wires to pins 1 & 6. It sounds like you're not getting dial tone into the KSU trunk ports.