CEA-770.2-D defines the physical characteristics of an interface and the parameters of the signals carried across that interface, using three parallel channels for the interconnection of equipment operating with analog component video signals. CEA-770.2-D includes specifications for: (1) 480i video format defined by 480 active lines, 525 total lines, 2:1 interlaced at 59.94 or 60 fields/second; and, (2) 480p video format defined by 480 active lines, 525 total lines, progressively scanned at 59.94 or 60 frames/second. Both video formats shall be capable of either 4:3 or 16:9 aspect ratios. Table 1 presents all the permissible scanning systems of CEA-770.2-D. A compliant interface shall implement one or more of these permissible scanning systems. Other scanning structures such as HDTV video formats are outside the scope of CEA-770.2-D (see CEA-770.3-C for HDTV scanning formats). The signal characteristics are defined by a gamma-corrected component set: a luminance video and two accompanying color-difference signals, see SMPTE Standard 170M Section 5.