What are the correct statements about ONU? (Multiple Choice)

Which of the following model control box heights are 3U? (Multiple Choice)

When delivered, the recommended load control frame is placed at the bottom of the cabinet; the storage settings are placed at intervals of 1U (1U = 44.45 mm) to facilitate management and reduce vibration transmission.

For the lifting of the antenna, traction is required to prevent the antenna from colliding with the tower.

If the data is improperly operated and the network construction takes place, it can be processed separately, and the relevant personnel will be informed after the network is completely restored.