In the United States, the three-digit code 877 is not assigned to any geographical location. As of 2015, this particular code is one of the series of six codes that are allocated for toll-free numbers.
The United States Federal Communications Commission regulates the use of toll-free numbers. Aside from the 877 prefix, other authorized three-digit codes reserved for toll-free numbers are 800, 844, 855, 866 and 888. SMS/800 provides a streamlined platform for the operation and management of toll-free numbers, which are covered under the North American Numbering Plan.
Toll-free numbers, such as those with the dialing prefix 877, work by enabling a calling party to reach the toll-free subscriber without incurring charges. The called party is responsible for paying the cost of the call. Aside from providing free-of-charge service for a calling party, toll-free subscribers also benefit from the portability feature of toll-free numbers. Since toll-free numbers are not geographically assigned to a particular city, subscribers can change service providers and still retain the toll-free number when they relocate to a new place.
In the U.S., toll-free numbers are prominently used by business establishments, such as in the telemarketing industry. As marketing tools, toll-free numbers enhance the accessibility of a company to its clients, employees and associates. These numbers are especially useful in providing technical support and customer service.