Well, basically, this is a ritual that mimics a straight forward action, namely talking to someone. In Thaumaturgy, distance itself is rarely a limiting factor.
What IS a limiting factor is the normal limitations of Thaumaturgy, namely that of a symbolic link. So you can't communicate with someone remotely if you don't have anything that is uniquely part of that person ... either an actual piece of him, like hair, or something that that person identifies with very strongly, like his 20 year wedding ring.
Other than that, the complexity of something like this is probably next to nil, like 2 or 3 maybe. Easily a single roll. This assumes the person isn't resisting. Otherwise, the minimum complexity would be (probably) their Conviction or Presence score plus two to compensate for Aspect usage.
Although if it crosses into the Nevernever, it might cost more, although I'm not sure.
Since you're establishing a visual link between the two sites, I'd definitely say Divination since you're seeing something that you wouldn't normally be able to see otherwise.