According to the Ford website, the feature is only used when you have (1) linked your mobile to the car's bluetooth, AND (2) have turned the Emergency Assistance on. It calls the standard emergency telephone number of your country (e.g. 911 in US, 112 in UK, 000 in Australia, etc).
For example, from the Australian entry on the site: "In the event of an accident severe enough to either trigger airbag deployment or shut off the fuel pump, Emergency Assistance uses your mobile phone, which must be within mobile reception range, to dial triple zero (000). Once connected, Emergency Assistance then transmits a message stating that your vehicle has been in an accident and provides the emergency services operator your precise GPS coordinates. The phone line remains open so that anyone in the vehicle may speak to the operator using the vehicle’s receiver."