In communications, any demand to set up a connection. 2. A unit of traffic measurement. 3. The actions performed by a call originator. 4. The operations required to establish, maintain, and release a connection. 5. To use a connection between two stations. 6. The action of bringing a computer program, a routine, or a subroutine into effect, usually by specifying the entry conditions and the entry point. 7. A customer attempt for which complete address information (e.g., 0-, 911, or 10 digits) is provided to the serving dial tone office.