1. If the number starts with a + symbol, the symbol is replaced with the International Prefix.
2. If the Country Code has been set:

   1. If the number begins with the Country Code, or International Prefix plus Country Code, the IP Office replaces them with the National Prefix.
   2. If the number does not start with the National Prefix or International Prefix, the IP Office adds the International Prefix.
3. If the incoming number does not begin with the National Prefix or International Prefix, the IP Office adds the Prefix.

Examples

• Prefix: 9 - The external dialing prefix used to make outgoing external calls.
• National Prefix: 90 - The expected prefix for outgoing national calls, including the external dialing prefix.
• International Prefix: 900 - The expected prefix for outgoing international calls, including the external dialing prefix.
• Country Code: 44 - The local country code.