| 1. | Higher order path tandem connection adaptation 高阶通道串联连接适配 |
| 2. | Higher order path tandem connection temination 高阶通道串联连接终端 |
| 3. | Lower order path tandem connection adaptation 低阶通道串联连接适配 |
| 4. | Lower order path tandem connection temination 低阶通道串联连接监视 |
| 5. | Lo - tcm : low order tandem connection monitor 低阶通道串联连接监视器 |
| 6. | Ho - tcm : high order tandem connection monitor 高阶通道串联连接监控 |
| 7. | Higher order path tandem connection monitor 高阶通道串联连接监视 |
| 8. | Lower order path tandem connection monitor 低阶通道串联连接监视 |
| 9. | Sonet . telecommunications - synchronous optical network - tandem connection maintenance 电信.同步光纤网 |
| 10. | Tandem connection monitor 串联连接监视 |