Phone calls have long been frequency filtered, digitized and multiplexed on lines, now mostly send over networks that can be easily ported to NSA. Edward Snowden could do it from Russia with the right S/W and right network authorizations.
And apparently did do that in Hawaii working for a freaking contractor, on overtime. Has happened before (Falcon and Snowman, for example- and always, always for a “greater righteous, self-ascribed morality”)