370 / | HD | MULTIPLEX COMMUNICATIONS |
464 | DF | COMMUNICATION TECHNIQUES FOR INFORMATION CARRIED IN PLURAL CHANNELS {9} |
480 | DF | .~ Combining or distributing information via frequency channels {11} |
493 | .~.~ Combined voice and data transmission {2} | |
494 | DF | .~.~.~> Data over voice |
495 | DF | .~.~.~> Data under voice |