455 / | HD | TELECOMMUNICATIONS |
39 | DF | TRANSMITTER AND RECEIVER AT SEPARATE STATIONS {14} |
500 | DF | .~ Plural transmitters or receivers (i.e., more than two stations) {4} |
507 | DF | .~.~ Central station (e.g., master, etc.) {6} |
517 | DF | .~.~.~ To or from mobile station {5} |
523 | .~.~.~.~ Using radiating transmission line |