If your goal is to use the ZTE F670L simply as a modem for a better third-party router, you may need to "unlock" the Bridge Mode setting which is often hidden via CSS or HTML:
The is an ONT (Optical Network Terminal) — a fiber-optic gateway/router provided by ISPs (e.g., Telmex, Claro, Telenet, DNA, etc.). Unlocking typically refers to:
