It is all tracked by the ESN in the phone. All systems keep logs and the providers can tell what area you are in - how would they know if you are to be charged for "roaming" if they couldn't track the position of the phone?????
A cell phone sends two signals, one for the actual conversation, one to indicate location to a repeater or cell tower to increase or decrease output signal of the phone. If you can provide info on the person, a cell provider could give a relative position to the requesting authority. Good thing is that these providers are PRIVATE companies and do not give that info freely.
I doubt that an active phone could be programmed from the provider to actually send a conversation without you keying in a number and press send, but it wouldn't surprise me.
Data transmission and cell tracking dates back to the original analog cell phones, Motorola "bricks" from the '80's.
I would doubt that they keep position records of where a person actually travels without setting up a trace program in advance. They don't keep movement activity maps on every user. They could do a real time track at the provider, though.
This is fact.
Edited to say: If I remember correctly, "Designers" - you, take information from "Engineers" - me, and make a dimensional drawing to manufacture. I have yet to see a "Designer" engineer a completed product. Not to flame you, of course. I worked on the cell tower infrastrure design - antenna's, combiners, filters, power amps and digital interface switching systems.