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PON-INTERMITENTE

Digi PON-INTERMITENTE on ZTE F6705 router: OLT registration

Verified with sources2 sourcesReviewed Oct 4, 2026
Technician coming? See the 2 steps they must show you
Fibre Wi-Fi router with antennas
Solijon SolayevCC BY-SA 4.0Image source

Risk level

Low

Usually safe to check without specialist tools.

Urgency

Medium

Quick answer

On Digi's ZTE F6705 router, a fast blinking green PON light means it is trying to register on the OLT, and a slow blink means it is updating. Wait without switching it off; if it does not turn solid, check the fibre and call Digi.

Safety first

Stop and check this first

  • Do not switch the router off while the PON light blinks slowly: according to the manual it is updating.
  • Digi's manual says not to look directly into the optical interface to avoid eye injury. Do not bend or pull the fibre cable and do not open the wall socket or the router.

Safe checks you can perform

  • Tell a fast blink from a slow one
  • Wait for registration to finish
  • Check the fibre and tell Digi

Leave these tasks to a qualified professional

  • Do not attempt this professional task: Check of the router's registration on the OLT
  • Do not attempt this professional task: Optical power reading

What a technician must be able to justify

Technician visit

These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.

These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.

  1. Check of the router's registration on the OLT

    What they doDigi checks from its systems whether your router appears on the OLT and why it does not complete registration, and fixes the provisioning or authentication if needed.

    They must show youthe router's status on the OLT and what they corrected.

    In writingthe ticket number, the cause and the date.

  2. Optical power reading

    What they doIf registration fails for lack of signal, the technician measures optical power at the wall socket and at the router to locate the section with losses.

    They must show youthe power reading in dBm.

    In writingthe measured value, the repair made and the date.

Before accepting a part or repair

Nothing has been shown yet. Do not accept a part swap based on the code alone.

Follow these steps

Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.

  1. Tell a fast blink from a slow one

    No special tools

    Who:
    you, looking at the front of the router.
    How:
    watch the PON light for a minute and note whether it blinks fast or slowly, and also whether the LOS light is off, solid or blinking red.
    Result that matters:
    knowing whether the router is registering or updating, and whether there is a fibre signal.
    If it blinks slowly:
    it is updating, leave it on until it finishes.
    If it blinks fast and LOS is lit:
    the problem is the fibre signal, check the cable and call Digi.
    Evidence to keep:
    short video or photo of the front with PON and LOS and the time.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

  2. Wait for registration to finish

    No special tools

    Who:
    you, without touching the router.
    How:
    leave the router on for a few minutes after start-up so it completes registration on the OLT, without unplugging it or pressing the Reset button.
    Result that matters:
    the PON light turning solid, which the manual defines as router registered.
    If it turns solid and the Internet light comes on:
    registration completed.
    If it keeps blinking fast for a long time:
    check the fibre connection.
    Evidence to keep:
    time it was switched on and time the light was still blinking.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

  3. Check the fibre and tell Digi

    No special tools

    Who:
    you, without opening the wall socket or the router.
    How:
    check the fibre cable is properly connected at the router's PON port and at the wall socket, without bending it or looking into the connector; if all is fine, contact Digi.
    Result that matters:
    ruling out a loose cable before asking for help.
    If the cable was loose and after reconnecting it registration completes:
    solved.
    If the cable is fine and the light keeps blinking:
    call Digi and describe the PON and LOS states.
    Evidence to keep:
    ticket number, date and photos of the lights.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain) · Manual de usuario ZTE ZXHN F8648P XGS-PON ONT (DIGI Spain)

Still not solved

If the error persists, stop here. See what the technician must do and show you.

Where this code applies

A code is meaningful only inside the right product and version context.

Primary scope

System
Networks
Brand
Digi
Product type
Fibre routers

Known code variants

  • digi fibra luz verde parpadea
  • digi luz pon parpadea
  • digi pon light blinking
  • digi pon verde intermitente
  • digi router not registered olt
  • digi router pon flashing
  • router digi no registrado olt
  • router digi pon intermitente
  • zte f6705 pon blinking
  • zte f6705 pon parpadeando

What it means

Digi's manual for the ZTE ZXHN F6705 describes the PON light as follows: solid, router registered on the OLT; off, not registered; fast blinking green, trying to register on the OLT; slow blinking green, updating. The OLT is the operator's equipment at the exchange. On Digi's ZTE F8648P the matching light is called Fibra, and the manual says that if it stays off or blinks green the link is not established or the ONT is not registered, and asks you to contact the provider. Other models may differ.

Warnings and stop conditions

  • Loweditorial warning

    Do not switch the router off while the PON light blinks slowly: according to the manual it is updating.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

  • Highsource verified

    Digi's manual says not to look directly into the optical interface to avoid eye injury. Do not bend or pull the fibre cable and do not open the wall socket or the router.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

Symptoms and causes

Probable causes · in order

  • Registration in progress after power-onCommon

    At start-up the router registers on Digi's OLT and the PON light blinks fast until registration finishes and it turns solid.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

  • Router updatingPossible

    If the blink is slow, the manual says the router is updating; it is not a fault and it is best not to switch it off.

    Evidence: Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

  • Registration not completingPossible

    If the blinking never ends, the router cannot register; for the F8648P the manual attributes this to link not established or ONT not registered and refers you to the provider.

    Evidence: Manual de usuario ZTE ZXHN F8648P XGS-PON ONT (DIGI Spain)

Virtual technician

Does PON-INTERMITENTE still appear after these checks?

Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.

Start diagnosis

Sources and technical references

  1. 1

    Manual de usuario ZTE ZXHN F6705 (DIGI Spain)

    DIGI Spain Telecom · 2026 · manual

  2. 2

    Manual de usuario ZTE ZXHN F8648P XGS-PON ONT (DIGI Spain)

    DIGI Spain Telecom · 2021 · manual

Sources: Manual de usuario ZTE ZXHN F6705 (DIGI Spain) · Manual de usuario ZTE ZXHN F8648P XGS-PON ONT (DIGI Spain)reviewed 2026-10-04 · verified

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