Once connected, you can use basic BusyBox or ZTE-specific commands:
Accessing the device via Telnet is often sought by advanced users to enable features like Bridge Mode or to gain higher-level administrative privileges. Default Status : Most modern ZTE gateways, including the , have Telnet (Port 23) closed by default for security. Firmware Hardening telnet zte f6640
If the web UI doesn't display optical power, use the command line. Once connected, you can use basic BusyBox or
This returns transmit and receive power levels. A healthy RX power is typically between -8 dBm and -27 dBm. telnet zte f6640