Unless you are using an old rotary dial analog phone, every kind of electronic communication is "data". Phone conversations are changed from analog to digital before they leave your phone. When it is recorded it is recorded as "data".
They are not only picking up every call on their servers, but they are storing every conversation as "data".
They have the capability of storing every electronic conversation. That is why they are building that huge data storehouse in Utah.
George Orwell had no idea that when Big Brother took over he could not only listen to conversations in real time, but go back years and pick up conversations that you have long ago forgotten you even had.