Telephone Codes are the numbers you dial when you want to reach someone in that particular country. It's also known as the country code.

International Direct Dial Codes are the numbers you dial when you want an international line from that particular country.

Emergency is the most common and quickest way to get connected to local emergency services (ambulance, police, fire, etc) when you are in a particular country. These do tend to change frequently - and they can sometimes vary from city to city.

For example, to call someone in Australia while you're in Argentina, you would dial 00-61 and then their phone number.