Essentially RFC 2806 specifies that there are two types of telephone URL:
- Global URLs begin with the "+" character and are followed by a digit string
that is unique worldwide.
- Local URLs do NOT begin with "+" and are a digit string that MUST be followed
by a "context" definition. The context of a Local URL specifies the Network
area (or areas) from which the digits of the URL are a proper dialing number
(i.e the area from which the digits will reach the desired destination)
So, most telephone numbers can be referenced by either a global or local
URL.
For example, the global URL for a telephone might be:
tel:+441234567890
Which is made up of:
- tel:
- This is a telephone URL
- +
- A global URL
- 44
- Country code for United Kingdom (UK)
- 1234
- Area code
- 567890
- The telephone number in the local area.
This telephone URL could also be written as a local URL: tel:01234567890;phone-context=+44 or tel:567890;phone-context=01234. It is important to understand
that if a local URL is used, it is necessary to define the context within
in which the number will work. The dialed number 01234567890 will only work
properly if it is dialed from a phone inside the UK Network. The dialed number
567890 will only work if it is dialed from a phone in the 01234 area.
Thus in order to support telephone URLs on
Blueworx Voice Response it is necessary to have
configuration data that enables two functions:
- Validation of the context of URLs.
- Access to the international dialing network.