Dative Case with Means of Communication

Did you know that we use the preposition по with the Dative case with means of communication, по радио, по телевизору, по телефону, по почте, etc.

For example,

По телевизору шёл концерт. There was a concert on TV.

Я послал тебе посылку по почте. I sent you a parcel by post.

Мы вчера говорили по телефону. We talked on the phone yesterday.