A line call is a term used in telecommunications to refer to the connection between two or more people. It is typically used to describe a telephone call, but can also be used to refer to other types of communication such as video conferencing. The term 'line call' is derived from the fact that the connection is made over a physical line, such as a telephone line or an internet connection. The answer to the crossword puzzle is 'NEXT', which is a reference to the fact that a line call is the NEXT step in the communication process.