| 1. | Catt ceramic audio tone transducer 陶瓷音频声调转换器 |
| 2. | Supervisory audio tone peak deviation 监测音峰频偏 |
| 3. | Supervisory audio tone sat 监测音频单音 |
| 4. | Supervisory audio tone 监测音频单音 |
| 5. | Power system protective relay applications of audio tones over voice grade channels 电话信道上可听音音调的电源系统保护继电器应用指南 |
| 6. | Guide for power system protective relay applications of audio tones over telephone channels 电话信道上可听音电源系统保护继电器应用指南 |
| 7. | Audio tones or lights clearly show which car has been assigned to carry the disabled passenger 就有语音或灯号清楚显示已被指定载送这位残障乘客的电梯。 |