Matt:
What you have is an ITT 601A KSU, one of the last 1A2 systems made by ITT. The card that you have is a 9-station rotary dial intercom unit. It may have a daughter board attached on it to adapt it for touch-tone use.
This card goes in the bottom slot only, in fact that should be the only slot that will hold it. Near this slot on the 66 block, you'll see rows of clips labeled "T and R" toward the very bottom. There won't be any dial tone on them, just talk battery. You will also see the next rows labeled "LG and L". These are for the line button's lamp. There are no A lead connections required.
In that same area of the block, you'll see ten individual clips numbered 0-9. Note that the numbers are stamped in between the rows, not along the block's fanning strip. You'll connect each buzzer each one of these digits. The other buzzer lead will connect to signal ground (any unused LG or A1 terminal will do). ITT sets use the orange/yellow pair for the buzzer. Western Electric sets use the yellow/green or yellow/orange pair. It really doesn't matter which pair you use.
Operation of the intercom is to simply go off-hook and dial the single digit desired. You won't hear any feedback at all and the intercom path isn't private. The buzzers receive a one-second burst of 10 volts AC when dialed, however they can be repeatedly dialed (or other digits) without hanging up the handset.
If you simply want "button and buzzer" signaling, you will need to have a 401A or 401B card installed in any regular line card slot. From there, you'll need to wire T/R, A and LG/L as if it was a standard line. I don't see the sense in doing this since it appears that you already have a dial intercom card.
