IMS version 22.6 & 22.9 > IMS Basics - User Guide 22.6 & 22.9 > Telephone Number Management (TNM)

When considering using any TNM system in the USA and Canada, one must be aware of the geographical nature of their telephone numbers. These numbers typically contain two standard prefixes: NPA and NXX.

NPA stands for Numbering Plan Area. This is also known as an area code, which is a three-digit number that identifies the phone service region. Each state is assigned one or more 3 digit codes.

For example:

The Canadian province of Manitoba has two NPA or area codes: 204 and 431.

The state of New Hampshire in the USA has one NPA of 603, whilst the state of New York has nineteen different NPAs.

NXX refers to the three-digit code forming the second part of a US 10-digit phone number (digits 4 to 6). This code is also known as the "central office code" or "exchange".

Each NXX is assigned to one phone company. If we consider that the 4 remaining digits can produce up to 10,000 numbers, phone companies were assigned numbers in blocks of 10,000. However, more recently, NANPA (North American Numbering Plan Administration) has been breaking up NXX blocks into groups of 1,000.

A useful source of area code information can be obtained from NANPA whose URL at the time of writing this document is:

https://www.nationalnanpa.com/index.html

We will now learn how to set up and use VC4’s TNM feature.

There are 4 main steps to follow in using TNM:

1.Telephone Number Range Type: Creating a new or selecting an existing one

2.Telephone Number range: Filling in the required supporting customer information

3.Set up the block ranges or sub ranges – (10,000 block or subranges of 1,000)

4.Assigning individual telephone numbers from those blocks to customers

We can consider the first 3 steps as part of an administrative role, whilst the last step is more of an end user assignment process.

Tel. Number Ranges: USA & Canada

Tel. Number Ranges: USA & Canada