| 340 / | HD | COMMUNICATIONS: ELECTRICAL | 
| 500 | DF | CONDITION RESPONSIVE INDICATING SYSTEM {6} | 
| 693.5 | DF | .~ Specified housing {3} | 
| 693.6 |  | .~.~ Configured to promote sensing capability (e.g., smoke detector) {1} | 
| 693.7 | DF | .~.~.~> Inserted battery required for housing closure |