Gravity Speech Synthesis V2 - What is AOP and AON?

I'd like to know what the AOP and AON connections on the circuit board are. I connected them to a scope and it looks like digital output (when a voice is playing through the speaker). If this is so, are there specs available such that I can make use of this digital output?

If not, is there an analog output so I can connect the output to a better amplifier and speaker?

Thanks for anyone's help!