Calling 000 from a mobile

Many mobile telephone users believe that dialing 112 in an emergency rather than triple-zero (000) will result in the call going via satellite if there are absolutely no mobile phone networks available. This is NOT true, and both 112 and triple-zero (000) rely on there being a signal from one of the mobile phone networks.

When GSM mobile phone networks first appeared in Australia the European (and “international”) emergency number of 112 (one-one-two) was used to route emergency calls through any available network, whereas triple-zero only worked through your own mobile provider network. For this reason the 112 number was widely promoted as a preferred emergency number on the mobile network as it would ensure the call was routed via any of the networks, would work with no SIM inserted, and would usually bypass any keypad lock.

The fact the number worked even if your own network had no signal meant the number obtained a reputation as an “always reach” emergency number, but in reality it still required a signal from one of the networks!

As technology improved the advanced features available to 112 were incorporated into the triple-zero (000) service, so in reality it no longer mattered which number you used. These features include (check your phone user guide for exact details):

  • Call will go via the mobile network with the strongest signal, even if that is not your own provider’s network (i.e. if you are with Telstra and the Optus network has a stronger signal, the call will go via Optus);
  • If your provider has no coverage but another provider’s network does, the call will go via that network;
  • Most phone keypad locks will allow calls to triple-zero (000) even while locked;
  • Calls to triple-zero (000) can be made with no SIM card inserted (or a damaged SIM card).

112 Does Not Go via Satellite!

Even some volunteer emergency service workers have promoted that 112 sends your signal via a satellite, so it should always be used rather than triple-zero (000). THIS IS NOT TRUE!

The technology inside a normal mobile telephone does not allow for signals to be sent via the satellites used for mobile phone calls.* Not only are the frequencies used different, the antenna used in a normal mobile phone is designed for stronger signals radiating from Earth, whereas a satellite phone antenna is built for weaker signals radiating from 640 – 1120km above the Earth for the Low Earth Orbit (LEO) networks, to over 30,000 km for others.

The majority of modern mobile phones will indicate if a network is available when your own provider is not, and therefore calls to triple-zero (000) can be made. For most smartphones this is indicated with the word “EMERGENCY” or “EMERGENCY ONLY” shown on the display. What this means is that while you have no signal from your own network (as indicated by the absence of signal bars, or “no signal” displayed), there is a signal being received from one of the other phone networks. The phone will therefore send any call to triple-zero (000) – or 112 – via that network.

If, however, the display shows “no signal” and there is no such indication, it means that none of the phone networks are being received and, therefore, regardless of what number you use no emergency call will get through!

* An after market add-on device for some mobile phones has appeared that when attached will allow the phone to send & receive signals via satellite, but this is an after market product that must be purchased and a separate satellite phone account established with a satellite phone provider. An example of these is the Optus “SatSleeve”. HOWEVER, most of these require a valid SIM and unlocked keypad to make an emergency call.

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