Remember, most all electronic 'exchanges' have dial in taps, ...
certainly all the CALEA systems in the US. The FBI can remotely tap any land-line phone, from any of their offices, in the USA.
The cell systems are a new source of information and as long as dumb criminals use their regular SIMS or don't turn their cells off, they leave one hell of a mouse droppings trail.
Mind you, a lot of dummies reside on Wall Street, too, as their cell phones turn up a lot of evidence that have put some way for decades. No time off for Federal crimes in the US, either.
Get smart, use Phil Zimmermann's new Silent Circle cell app, he has never catered to cops sticking their noses in too your business. Coming soon. (Still won't beat Geo-location, though)