Pick up and Ring up

Pick up verb - To acquire complete knowledge, understanding, or skill in.

Ring up and pick up are semantically related In some cases you can use "Ring up" instead a verb "Pick up".

Ring up verb - To make a telephone call to.

Pick up and ring up are semantically related in telephone topic. Sometimes you can use "Pick up" instead a verb "Ring up", if it concerns topics such as communicate through telephone system.