What is the meaning of 2 long blast?

Two long blasts typically signify a specific signal or alert in various contexts, such as maritime communication, signaling in the military, or emergency alerts. In maritime contexts, for example, two long blasts from a ship's horn often indicate its intention to pass another vessel or a warning of its presence. In other situations, it may serve as a call for attention or an alert for action. The exact meaning can vary depending on the specific protocol or system in use.