Emergency telephone number
Many countries’ public telephone networks
have a single emergency telephone num-
ber, sometimes known as the universal
emergency telephone number or occasion-
ally the emergency services number, that
allows a caller to contact local emergency
services for assistance. The emergency tele-
phone number may differ from country to
country. It is typically a three-digit number
so that it can be easily remembered and
dialed quickly. Some countries have a differ-
ent emergency number for each of the differ-
ent emergency services; these often differ
only by the last digit.
Emergency numbers and
mobile telephones
Mobile phones can be used in countries with
different emergency numbers. A traveller vis-
iting a foreign country does not have to know
the local emergency numbers, however. The
mobile phone and the SIM card have a pre-
programmed list of emergency numbers.
When the user tries to set up a call using an
emergency number known by a GSM phone,
the special emergency call setup takes place.
The actual number is not even transmitted in-
to network, but the network redirects the
emergency call to the local emergency desk.
Most GSM mobile phones can dial emergency
calls even when the phone keyboard is
locked, the phone is without a SIM card, or
an emergency number is entered instead of
the PIN.
Most GSM mobile phones have 112, 999
and 911 as pre-programmed emergency
numbers that are always available.[1] The
SIM card issued by the operator can contain
additional country-specific emergency num-
bers that can be used even when roaming
abroad. The GSM network can also update
the list of well-known emergency numbers
when the phone registers to it.
Using an emergency number recognized
by a GSM phone like 112 instead of another
emergency number may be advantageous,
since GSM phones and networks give special
priority to emergency calls. A phone dialing
an emergency service number not recognized
by it may refuse to roam onto another net-
work, leading to trouble if there is no access
to the home network