Final answer:
A CAPT Call on the Interphone is for everyday communication among the ship's crew, while an EMER Call is used for urgent communication during emergencies.
Step-by-step explanation:
The Interphone is a communication system used on ships. A CAPT Call stands for Captain's Call, which is a mode of communication used for everyday communication among the ship's crew members. It is not limited to captains only. On the other hand, an EMER Call represents Emergency Call, which is used for urgent communication during emergencies. It is typically initiated by the ship's emergency services or personnel in charge of handling emergencies.