American Standard Vent Away

[wkillpatri]

We just bought a house that has several American Standard "Vent Away" wall-mounted toilets. Does anyone know what is so special or unique about this toilet? I can't find any information about it. To flush, one pushes the handle in. To vent, one pulls the handle out. However, I don't want to use the vent feature until I have some idea of what it does! Thanks.