How Does A Toll Free Number Work? (Infographic)

How Does A Toll Free Number Work? (Infographic)

Toll free numbers have had a long history. From the days of the Zenith number, introduced in the 1930’s, through to today, the history toll free is full of twists and turns. The regulations that established how toll free numbers work today were passed in the Telecom Act of 1996, and the overall process of how they are routed has not changed much since. So, how exactly does a toll free number work?

History of Toll Free

The concept of allowing consumers to connect with businesses and government agencies for free began early on in telecom’s history. The Zenith Number, introduced in the 1930’s, allowed callers to connect with businesses free of charge by asking the switch board operator to connect via “Zenith”. This was a manual process that required a human operator to make the connection.

Zenith numbers all but disappeared after the introduction of direct dial 800 numbers in 1967. These numbers offered a flat rate long distance calling service that, like their predecessor, allowed consumers to call businesses and government agencies free of charge. Known as WATS (Wide Are Telephone Service), this first iteration of the toll free number grew quickly in popularity, and by 1976 had earned AT&T over $1 billion in revenue.

AT&T’s hegemony over the telecom world came to an abrupt end in 1984 with the breakup of the Bell System. The breakup created conditions within the industry that allowed for greater competition between telecom providers. Yet, the industry was still tightly regulated via the 1934 Telecommunications Act, and so the industry’s growth remained lackluster. Not until the 1996 Telecommunications Act did this change. The 1996 Telecommunications Act sought to promote competition and reduce regulation in order to secure lower prices and higher quality services for telecommunications consumers and encourage the rapid deployment of new telecommunications technologies, which included the internet.

The 1996 Telecommunications Act was important for toll free because it fleshed out the rules surrounding how toll free numbers should work. It established a central database, called the SMS/800, which stores all routing information for toll free numbers. This database is a crucial piece of the complex weave that is toll free number routing. The Act also established independent entities, called Responsible Organizations (RespOrgs), responsible for managing toll free routing information within the SMS/800 database. For the first time, these entities could be completely independent from carriers, although carriers could (and do) establish their own RespOrg entities as well.

How Does a Toll Free Number Work?


Toll Free numbers are managed from the central database called the SMS/800 (now SOMOS). When a toll free number is dialed by a consumer, the call first passes through a local telephone company. This could be your local landline telephone company, or your VoIP provider. The local telephone company does a data dip of the SMS/800 database to ascertain which long distance telephone company is responsible for the toll free number dialed. Once the local telephone company receives that information, it then routes the call to the appropriate long distance telephone company. The long distance telephone company is then responsible for routing the call to the destination local telephone company or VoIP carrier, who then patch the call through to the end user. While this process may seem long, in most cases it all occurs in under three seconds.


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