オプトアイソレータブレイクアウト

I should have inspected the schematic more closely. Each output (from the opto-coupler IC) is buffered by a transistor in common-emitter configuration with a 10K pull-up resistor. It can't be used to drive a relay or other load. When the input goes high (logical-1), the opto-coupler IC becomes active, grounds the base of the output transistor, which then turns off. The output then goes to logical-1, pulled high by the 10K pull-up. I ended up buying a couple of naked opto-coupler chips, and tossed this breakout board into the parts bin for a future project.