AmbitiousPearMosquito7751

I'm trying to pick a new bilevel apnea machine, but am confused by the specs called out in the table at the bottom of the following page:

http://www.resmed.com/us/en/consumer/products/devices/aircurve-10-asv.html

Anyone know what the following features mean for a bilevel autoadjusting apnea machine?

S T ST Trigger and cycle

The manuals seem to describe the other specs in the table at the bottom of the page.

Thanks for any info, Chris