U.S. PHONE NUMBERS DATABASE
All telephone numbers in the U.S., including numbers of of street pay phones, consist of seven digits and 3 digit area code. Many companies take the opportunity to choose the combination of signs when installing the phone, for promotional purposes and for a better memorization of their number selecte it so that it can be represented in the form of the word (by letters marked above digits of telephone). This word is usually associated with the name or the profile of the company. Large companies, operating in the service sector, for its regular and prospective customers have numbers of free communication (toll free numbers), which you can call from anywhere in the country (payment for call is assumed by the firm). These numbers have a three digit code 800. When dialing of these companies,you need to dial digit 1 before the index 800. All phone numbers, on which payed information or any additional service is provided, before the seven-digit number have a code 900.
This database of phone numbers can be very helpful in the case, if the area-code of phone number is unknown to you and when you know the phone number, but don't know the city, to which this phone number is binded