340 / | HD | COMMUNICATIONS: ELECTRICAL |
907 | DF | TRAFFIC CONTROL INDICATOR {8} |
909 | DF | .~ Plural intersections under common central station control {5} |
910 | DF | .~.~ Central station responsive to traffic detectors {1} |
911 | .~.~.~ Central station controls offset (time between beginning of same phase at adjacent intersections) |