Numero

This tiny gem contains helpers for validating North American phone numbers.

Add it to your Gemfile, or install as a plugin.

Usage

Ruby:

Numero.valid_number?('15554442222') #=> true
Numero.valid_number?('194512') #=> false

Rails:

class User < ActiveRecord::Base
  acts_as_numero :number
end

u = User.new(:number => '1234')
u.valid? #=> false

The North American Numbering Plan

Numero validates phone numbers based on the North American Numbering Plan.

The NANP breaks phone numbers into 4 components:

|A| B | C | D |
+1-555-444-2222

A. ITU country code
B. NPA  - area code
C. NXX  - Central Office code (exchange)
D. XXXX - Subscriber Number

Each section allows for a specific set of numbers:

• ITU: This is always +1 for North American numbers, although, it is most often written without the +.
• NPA: First digit must be in the range [2-9], second and third digit can be any number [0-9].
• NXX: First digit must be in the range [2-9], second and third digit can be any number [0-9].
• XXXX: [0-9] for each digit