See, which is why I say it could make sense, except you'd have to come up with the assumptions yourself.. Which ends up making it clunky. There was nothing that says the talisman was still at work, it's just a possibility we toss out there to give sense to the phone. Had the author shown the link btw the new magic and the old spell, all of this couldve been put to rest. But as it is, talisman and phone are still two unrelated items in terms of magical power.