I am a programmer myself, so I am aware of how incredibly annoying interruptions are. I loathe being thrown out of the zone. So yes, I am very aware of whatever others are doing at the time of calling. I only call, if I believe it will shorten the interaction on both ends and would add something meaningful, and I am certain I am not interrupting the other person. I largely prefer email though, as it is more async and generally more convenient.