In the US, the receiver effectively covers the cost of mobile calls—though it’s a bit nuanced, so apologies for any lack of clarity. You’re essentially paying for incoming calls if you’re on a metered plan, since those minutes get deducted. With most rate plans now being unlimited, this cost is somewhat hidden.

In Japan (the only other system I’m familiar with), it works differently: the caller is charged for the recipient’s end, while the receiver pays nothing. For example, calling a mobile phone from a landline costs more to account for the mobile portion. I remember years ago using a prepaid phone card from a payphone to call a mobile number—the balance drained incredibly fast. This is one reason why younger generations in Japan rarely rely on PSTN for routine calls, since it can quickly become expensive.