A red LOS light on an Octotel ONT means the optical signal from the fibre network is not reaching your device. This usually indicates a fibre break, disconnected patch lead, or area-level fault. If LOS stays red after proper restart and cable checks, escalation to Octotel is required.
What the Problem Means
On an Octotel ONT, a red LOS (Loss of Signal) light indicates the ONT is not detecting incoming optical light from the access network.
This is a physical or access-layer issue, not a router, WiFi, or gaming performance problem.
In South Africa's fibre model:
- The User manages ONT power and patch lead
- The ISP manages provisioning and ticket logging
- Octotel (FNO) maintains the fibre infrastructure outside the property
A persistent red LOS means the optical path between your home and the street distribution point is interrupted.
Why It Happens
Common Octotel LOS triggers:
- Fibre break in the street or building riser
- Patch lead bent or partially unplugged
- Maintenance work in the area
- ONT reboot during loadshedding with failed re-sync
- Cabinet-level fibre damage
If LOS is red and PON is off, no optical signal is reaching the ONT.
Octotel ONT Light Meaning Table
| Light | State | Meaning | Fault Layer | Action |
|---|---|---|---|---|
| Power | Off | No power | User | Check adapter/UPS |
| Power | Green | ONT powered | — | Continue checks |
| PON | Flashing | Attempting sync | Registration | Wait 2–5 min |
| PON | Solid Green | Registered | Network OK | Normal |
| LOS | Red (Solid/Flashing) | Optical signal lost | Access Layer | Diagnose fibre path |
| LAN | Off | Router not connected | Internal | Check Ethernet |
Key interpretation:
- LOS red → Fibre signal failure
- PON solid + LOS off → Fibre signal stable
- LAN off but PON solid → Not a fibre fault
Step-by-Step Diagnostic Checklist
Confirm Power Stability
- Ensure ONT is powered directly or via stable UPS.
- Power interruptions during loadshedding are common.
Inspect Fibre Patch Lead
- No sharp bends.
- No visible cracks.
- Fully inserted.
- Do not touch fibre tip.
Perform Proper Power Cycle
- Switch OFF ONT.
- Wait 2 minutes.
- Switch ON.
- Allow 5 minutes for full sync.
Observe Light Sequence
- Power solid.
- PON blinking.
- PON solid.
- LOS off.
- If LOS returns to red and remains red, signal is not present.
Check for Area-Level Fault
- Confirm with neighbours using Octotel.
- If multiple homes have red LOS, it is likely a network-level issue.
Definition: Fibre Break vs Patch Lead Fault
Occurs when the external optical cable between your home and the street cabinet is physically damaged.
Refers to the short internal fibre cable connecting the wall box to the ONT.
Both cause LOS, but only patch lead issues can be resolved internally.
When to Escalate
Escalate when:
- LOS remains red after proper restart
- Patch lead appears intact
- No indoor cable damage
- Neighbours report similar outage
Typical Octotel repair windows in South Africa:
- 24–48 hours for isolated signal faults
- Up to 72 hours for fibre break requiring technician dispatch
The ISP cannot repair the physical fibre line. Octotel must restore signal at the access layer.
Responsibility Breakdown
| Layer | Responsible Party |
|---|---|
| ONT power & internal patch lead | User |
| Provisioning & support ticket | ISP |
| Fibre line & street infrastructure | Octotel (FNO) |
Clear layer identification prevents unnecessary router resets and WiFi troubleshooting.
When This Is NOT the Issue
If all of the following are true:
- PON is solid green
- LOS is off
- Internet works but is slow
Then this is not a fibre signal issue.
See our fibre speed & performance guides