FM-8000
20 input slots and 20 output slots, maximum of 80 input and 80 output
FM 3600
9 input slots and 9 output slots, maximum of 36 input and 36 output
FM 1600
4 input slots and 4 output slots, maximum of 16 input and 16 output
FM 800
8 input slots and 8 output slots, maximum of 32 input and 32 output