380 TVL Camera Resolution?

TVL resolution originated as an analog standard and meant the number of black vertical lines on a white background that could be distinctly viewed and counted. So 320 lines would require 640 pixels, half white and half black. Thus in the fairly early days of transferring analogue video to digital, a 640 x 480 frame size provided essentially broadcast quality video, if digitized at a high quality level (i.e with not a lot of compression).

NTSC has 525 scan lines, but some at top and bottom are not usable, so 480 pixels is adequate to fill the displayed lines.