Would POLL_TIME = CONSTANT + GEOM eat more cpu once it hit the 2m max? If not, I'd favor this method as sms's seem to go in conversations (e.g. a friend and I will txt frequently over the course of a 5 minute discussion, and then not again for hours or days).

And is One Ring a separate app, or added functionality to dialcentral? (I'm sure it's been addressed here previously, apologies if the question has become tiring).