The ZTE box should connect over LTE, but if the antenna LED is turning orange during calls, it may be falling back to a UMTS connection, which could explain the lower call quality. Please try restarting the device and ensuring it's placed near a window or in an area with strong signal strength.
If your ZTE box is switching to UTMS even when placed near a window, it could be struggling to maintain a strong LTE signal. Try repositioning the device to an area with better reception or checking for any obstructions. If the issue persists, we recommend contacting tech support for further assistance.
