About smart dialling
With the smart dialling feature, you can set a default country code and area code for phone numbers in the Contacts application so that you don't have to dial a country code and area code each time that you make a call, unless the country code or area code are different from the default codes that you set. Some country codes aren't supported by the smart dialling feature.
In the smart dialling options, you can also specify the main phone number for an organisation that you call frequently so that you can quickly call a contact in that organisation by only dialling the extension for the contact. If you add contacts from that organisation to your contact list, when you add their phone numbers, you can type just the extensions instead of typing out the main phone number for the organisation.