How do i unclog a drainline on a dishwasher?

first of all there is no garbage disposal. no air gap or whatever on the sink. the drainline runs from the dishwasher to the sink drain pipe. i took it off yesterday and tried to blow back into the dishwasher to hear air bubbling in the water and it didnt. it was straight clogged. first of all is there a ball valve or something under the dishwasher? two is how do i unclog it? i probably need air compressor but is it safe to blow high powered air into the dishwasher? i removed the cover in the bottom of the dishwasher and stuck my hand in there and didnt feel any basket. its a ge model