Poor signal or LOS
Symptom: unstable, slow, dropping connection — or the CPE is in LOS (loss of optical signal).
Quick diagnosis
Poor signal / LOS
Open the CPE's Optics tab
CPE Rx?
No signal / LOSPhysical fiber problem → Technical visitBelow -27 dBmWeak signal - degradation → Technical visitBetween -8 and -25 dBmSignal OK - investigate another cause
Step by step
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Open the CPE and go to the Optics tab. Click Sync to get the current value.
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Read the CPE Rx (power received by the ONU):
- Between -8 and -25 dBm → healthy signal. The problem is probably not optical; go back to Customer with no connection and investigate WAN/WiFi.
- -25 to -27 dBm → attention, starting to degrade.
- Below -27 dBm → weak signal; high chance of instability.
- No signal / LOS → total loss.
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Cross-check with the Events tab: many drops/reconnects confirm physical instability.
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Check whether the problem is isolated or collective: use the Signal Level Report filtering by the same OLT. If several customers on the same OLT/PON port are poor, the problem is in the provider's network (backbone/splitter), not at the customer's home.
Most common causes
| Cause | Indication | Action |
|---|---|---|
| Broken fiber | Sudden LOS | Technical visit |
| Dirty/loose connector | Very low, fluctuating signal | Field cleaning/reconnection |
| Bend/kink in the customer's fiber | Weak signal on only this customer | Fix the installation |
| Splitter/network problem | Several customers on the same OLT poor at once | Escalate to engineering/NOC |
| Signal too strong (above -8 dBm) | RX too strong | Field attenuation adjustment |
When to escalate
- LOS or weak signal on one customer → technical visit.
- Poor signal on several customers on the same OLT/port → engineering/NOC (infrastructure problem).