A screen pop, also known as a call pop is an action that takes place in Trello when a user receives an incoming phone call. Loup is a Google Chrome extension that connects your phone system (PBX) to Trello via APIs. When a user receives an inbound call, Loup grabs the phone number (DID) from the phone system (PBX), opens a new tab in Google Chrome and automatically searches Trello for any information tied to that phone number (DID). Loup’s call pops are like caller ID on steroids.