The crossword solution for the term COMMUNICATIONS 'A' is ALFA, which stands for the Automatic Link Establishment (ALE) Frequency Agility. ALE is a protocol used in radio communications to establish and maintain a connection between two or more radio devices. It is used in military and civilian applications, such as air traffic control, maritime communications, and emergency services. ALE is also used in amateur radio networks, allowing users to quickly and easily connect with each other.