An overview of the current state of intelligent network (IN) standards as described on CCITT's capability set 1 (CS1) is presented. The key to the success of CS1 lies in it being simple enough to be realizable with limited impact on existing software technology and network signaling, rich enough to provide a nontrivial, commercially deployable, initial set of services, and open-ended for growth, both in terms of service richness and penetration, and new capabilities enabled by new technologies. The objectives of IN and CS1, the main characteristics of CS1, and the framework and directions for IN evolution are discussed.