I'm not sure what you mean in saying that "the LATCC for not calling the controller...? LATCC radars - at least those in TC - are equipped with conflict alert systems. If the machine thinks two aircraft are going to conflict an alert signal appears on the display. The alerts are in two phases - first when there is often considerable distance between the aircraft and second when there isn't!! The only warning which a controller receives is when the alert appears on the radar tube - nobody comes along and tells him (except after the event!); he is expected to react speedily and take action to resolve any conflict. I say "any conflict" because our system is somewhat cautious and acn throw up alerts which require no action to be taken - typically alerts appear on fast climbing aircraft because the system doesn't know the climb is going to be stopped.. I wasn't aware that LATCC had to alert other ATC agencies if a conflict was detected affecting their traffic - in any event, by the time a phone call was made, etc, the problem would have been resolved.