Design the interfaces of components that might be used in a system for an emergency control room. You should design interfaces for call logging component that records calls made, and a vehicle discovery component that, given a post code (zip code) and an incident type, finds the nearest suitable vehicle to be dispatched to the incident. I am confused to design call logging components, I came up with this figure for second part of the question. Can anyone suggest me how to proceed ?  I need a help.