Didnt this cause some concern this week with three clients all complaining about NO INTERNET or SLOW INTERNET

What they were not aware of was how the TELSTRA SMART MODEMS operate and what the end user experience is when it switches to MOBILE MODE or 4G Backup

For those of you who dont know how they operate, in short, the Modems will operate on the FIXED NBN LINE where you will obviously achieve your maximum speeds and use your Home Phone Landline (if you still have one)

However, the Modems also have what they call a 4G Backup which basically means there is a 4G SIM CARD attached to the Modem and when the Modem detects that the FIXED NBN LINE is not working, the MODEM switches to the 4G Backup via the Mobile network to continue your service.

Keep in mind that whilst your service “continues” in this mode, it does not give you full service speeds and coverage and this is where many of you are getting caught and confused thinking that it should always be up and working as per the plan you paid for but alas, that is not how they work.

They are called “SMART” for various reasons with one of them being that they will switch back to the NBN FIXED LINE when it detects that the line has been rectified.

However, the feature does not always work and you sometimes need to “wake it up” to get it to do its job.

So what do the lights on your Telstra Smart Modem mean?

The Smart Modem Gen 2 and Gen 3 are Telstra’s newest Smart Modem, bringing the latest hybrid technology to your home broadband and allowing you to:

  • Connect sooner– Get online even before your home broadband is activated with your Telstra Smart Modem Gen 2. Its inbuilt, pre-activated SIM can connect to Telstra’s mobile network right out of the box.
  • Have a built-in backup plan– No home broadband due to network upgrades or bad weather? Your Telstra Smart Modem  will automatically switch to Telstra’s mobile network if required, so you’ll be back online in minutes, as long as 4G coverage is available.
    Mobile speeds are limited to 6/1 Mbps and will vary with local conditions and content.

Understanding the lights on your Telstra Smart Modem  can help keep you informed of your internet connection status, and help diagnose problems if you’re having connection difficulties.

The simplest way to diagnose the Modem is firstly look at the light on the FRONT PANEL.

If it is a SOLID GREEN, then it is working via the NBN FIXED LINE

If it is SOLID BLUE, then it is working on the 4G MOBILE BACK UP.

If your ISP advises you that the NBN FIXED LINE fault has been repaired but your Modem still shows the BLUE light, then reset the Modem by performing a basic power cycle. (Turning it off then back on)



LED LED Behaviours Cause
Front LED Off Powered off
Green Fixed online
Blue Mobile online
White Powered on, booting up
White Flashing Firmware upgrade. Interval 0.5 seconds until download complete
Orange Finished booting up and trying to connect / Fixed connection lost, trying to reconnect and waiting to failover to mobile
Red Both fixed and mobile failed to connect, trying to connect on both
Colour Cycle Factory Reset. Interval between colour cycle 0.5 second.
ONLINE Green Fixed or Mobile Broadband online.
Orange ADSL captive portal (newdsluser)
Red PPP authentication failure
Off Fixed & Mobile offline.
WAN/DSL Green Ethernet connected / DSL synced
Green (slow flash) DSL start syncing
Green (fast flash) DSL finish syncing
Off No fixed physical connection






Green Mobile online – this is expected when running on mobile backup, i.e. Front LED is blue.
Off Mobile offline – this is expected when nbn is online, i.e. Front LED is green.
MOBILE SIGNAL Green Good signal
Orange/Yellow OK signal
Red Poor signal
Off Telstra network unavailable


(SIP Mode)

Green Registered
Green Flashing DECT handset or FXS off-hook. Interval 1.0 sec.
Red Unable to make a call
Orange SOS call only (fixed unavailable, Telstra mobile unavailable)
Off Not registered, e.g. no SIP credentials.


(PSTN Mode)

Green Voltage detected on PSTN Port
Green Flashing DECT handset off hook. Interval 1.0 sec.
Off No Voltage detected on PSTN port
WI-FI Green On
Off Off
PAIR Green DECT paired or WPS paired
Green Flashing Pairing mode. Interval 0.5 sec
Green Flashing Paging mode Interval 2 sec
Red WPS timed out or failed


Patrick Larobina