| Normalling | Symbol | Behavior | |------------|--------|----------| | | FN | Top jack → Bottom jack automatically. Plugging into top or bottom breaks the internal connection. | | Half Normal | HN | Top jack → Bottom jack automatically. Plugging into top does not break bottom; plugging into bottom breaks top. (Used for mults/splits). | | Open (Non-Normal) | NN | No internal connection. Top and bottom are independent. |
This is the most ignored but most critical diagram. Improper grounding causes 60Hz hum (or 50Hz). Recording Studio Wiring Diagram