• Result: It passes traffic efficiently without the overheating issues often seen when these units act as primary routers.
• Limitation: The F689 is a GPON standard device. While it can technically handle 2.4Gbps downstream, the internal switching architecture often limits actual throughput to around 900Mbps–1.4Gbps in real-world scenarios. If you have a 2Gbps or faster plan, this unit will likely be a bottleneck even in bridge mode.

6. Common Issues & Solutions

| Problem | Likely Cause | Fix | |---------|--------------|-----| | No internet after enabling bridge | Router not set to PPPoE/DHCP (depending on ISP) | Configure router’s WAN interface accordingly | | Cannot access ONT web interface | Management IP lost | Factory reset ONT or connect via untagged management VLAN | | Only LAN1 works | Exclusive bridge limited to one port | Use LAN1 to connect your router | | Wi-Fi still active | Not disabled automatically | Log in (if still possible) and disable, or ignore since it’s on different subnet | The Ultimate Guide to ZTE F689 Bridge Mode

Ensure the VLAN ID remains the same as it was in Route mode; this is critical for your ISP to recognize the traffic. 4. Bind the Port Turn off DHCP on the F689:

• Many ISPs preload the F689 with firmware that exposes limited settings. Bridge-mode capability varies: some firmwares provide a straightforward “Bridge” or “IP passthrough” option; others lock routing features or use proprietary management.
• When bridge mode is not explicitly exposed, configurations like DMZ+ (DMZ for a single WAN MAC/IP) or PPPoE passthrough are sometimes offered as alternatives.

• Wi-Fi: Turn off.
• DHCP server: Disable.
• Firewall: Disable (since bridge bypasses it anyway).