The relays that were used to switch A/V in EC areas were IBM wire relays which MAX energized.
They came in many configurations 4-8-12-24 and I believe 48 contact units.
They were Normally-open and Normally closed on each contact (spdt).
I couldn't remember FAVAG!
P.S. They were Lap and Gap relays..
Lap = Make before Break
Gap = Break before make