Systems and networks of the fixed service operating via terrestrial stations.
| Working Party 9A (WP 9A) | Performance and availability, interference objectives and analysis, effects of propagation and terminology |
| Working Party 9B (WP 9B) | Radio-frequency channel arrangements, radio system characteristics, interconnection, maintenance and various applications |
| Working Party 9C (WP 9C) | HF systems |
| Working Party 9D (WP 9D) | Sharing with other services (except for the fixed-satellite service) |