A toll free number is a special kind of telephone number provided by a commercial entity to cater to its customers. In this kind of numbering system, a customer is not charged for calling the number. Instead the commercial entity pays for it. The payment is based on a number of factors, which include number of calls and cost of trunk lines. Some telephone companies even charge a monthly flat rate for this kind of service. Toll free numbers are sometimes allotted to residential or a cell phone number.

Toll free numbers are often referred to as 800 numbers. The number 800 is the original area code that was used with toll free numbers. Now more area code numbers such as 888, 877, 866, and 855 are being used. Newer numbers such as 844, 833 and 822 have been allotted but are not yet active.

In the US, toll free numbers are provided by both Inter-exchange Carriers and Local Exchange Carriers. These numbers are not geographic in nature; a sharp contrast to the local telephone numbers. A toll free number can be located anywhere across the nation, or maybe even abroad. The physical location of such a number is determined by the telephone operator using an intelligent network mechanism. A toll free number is then translated into a normal geographic number and then routed in the usual manner through the local telephone exchange.

The routing of a toll free number in the US is handled by Inter-exchange carriers such as Sprint and AT&T. A company which wants to provide toll free number service chooses a Responsible Organization (RESPORG) to maintain them. A RESPORG is actually an Inter-exchange carrier that is going to provide the necessary services.

A company can share its toll free numbers among various Inter-exchange carriers. The task of determining which Inter-exchange carrier handles the call is performed by the LEC. Once the carrier is traced out, the call is forwarded to the carrier's point of presence (POP). The routing of the call is then performed by the carrier's SCP using a protocol called Signaling System 7. The call is finally routed to the company's trunk lines, wherein a PBX system handles the call.

This article is written for AccessDirect, providers of Unified Messaging, Voice Mail, and Virtual/Hosted PBX Phone systems with local and toll free numbers. Visit us at www.messagingservice.com

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