Matt:
I've done a little more research. On the intercom card itself, check the jumpers on TC1 and TC2. These are near the edge connector. These should both be in the "B to C" positions for buzzers. TC1 affects the even-numbered stations and TC2 affects the odd-numbered ones. Both should be set the same way.
For 10 volt buzzers, run a single jumper from row 1, terminal 5 to row 35, terminal 6.
For 18 volt buzzers, run a single jumper from row 28, terminal 6 to row 35, terminal 6.
Note that row 35, terminal 6 is the buzzer voltage input to the intercom card. Do not install both jumpers.
Lastly, your card may utilize two-digit dialing, meaning that the dial codes are 10-19 instead of single-digits.
