| 359 / | HD | OPTICS: SYSTEMS (INCLUDING COMMUNICATION) AND ELEMENTS |
| 109 | DF | OPTICAL COMMUNICATION {13} |
| 154 | DF | .~ Transmitter and receiver system {15} |
| 164 | ![]() | .~.~ Plural stations {3} |
| 165 | DF | .~.~.~> Address directing connections |
| 166 | DF | .~.~.~> Unidirectional or loopback |
| 167 | DF | .~.~.~> Central or master station |