Almost all cell phones in Argentina operate with a calling party pays (CPP) system. That means that whoever initiates the call pays for it. For this reason, cell phones in Argentina usually start with number 15. Since calls to cellphones are more expensive than land calls in Argentina, this prefix indicates the calling party that this call is going to cost more. For instance if a user wanted to call a Buenos Aires CPP cell phone, from within Buenos Aires, they would have to dial: