In the pilot episode children of the gods apophis dials in to the SGC with a few personal guards the gate shuts down and then theres a fight with a few airman and jafa after apophis loses a few men he decides to leave but how can he dial out the gate shut down but somehow its magically open
Mary was it?? ok , well in the second SG1 movie where teal'c is under the service of Ba'al and then he must avenge his 'gods' death as the first prime. He therefore uses a small device which he attaches to the stargate and dials to the planet where Ba'al was able to monitor solar flares through real time.i'm sure you posted this qn a while back before the movie, i guess that it just shows that the show has an explanation for everything and any paradox.