The SCTE has begun revising three standards dealing with SCTE 35-based program-specific ad insertion.SCTE 118-1 2006, Program-Specific Ad Insertion - Data Field Definitions, Functional Overview and Application Guidelines, defines the functionality associated with the scheduling and insertion of a spot into a digital broadcast program based on the program identifier passed in the SCTE 35 cue message.SCTE 118-2 2007, Program-Specific Ad Insertion - Content Provider to Traffic Communication Applications Data Mode, describes the information required to communicate the program and avail structure from a network to an affiliate's SCTE 35-compliant traffic system.SCTE 118-3 2006, Program-Specific Ad Insertion - Traffic System to Ad Insertion System File Format Specification, defines the information passed from an affiliate's traffic system to an affiliate's ad insertion system for communications of ad insertion schedules, including unique program identifiers where specified. It specifies the required data for multi-tiered, program-specific insertion, as well as the file format for the data communications.