[vidarh]

On cell phones. This is for the same reason as you have to pay for receiving calls while roaming internationally on cell phones - basically the difference is a historical fluke based on numbering plans and how billing are done for landline calls.

US local calls don't have per-minute changes. And cell phone numbering is not using a separate number sequence as in most other countries (e.g. in UK all cellphone numbers start 07x where x is 4 or above, so everyone knows when calling a cellphone).

Because of that, it'd be unreasonable to charge callers for cellphone calls, as people don't have an easy way of knowing if they're making a local landline call or calling someone on a cellphone that's potentially at the other side of the country, or abroad.

Similarly for international roaming we pay to receive in Europe too, as the caller don't know if the cellphone is abroad. Except caller pays whatever their plan would normally charge if the phone was in the country its numbering plan indicates, and the roaming charges covers the rest.