Call up and Get someone on the horn

Call up verb - Get or try to get into communication (with someone) by telephone.

Get someone on the horn and call up are semantically related in telephone topic. In some cases you can use "Get someone on the horn" instead a verb "Call up".

Call up and get someone on the horn are semantically related in telephone topic. You can use "Call up" instead a verb phrase "Get someone on the horn".