The Bell System was a network of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated telephone service in North America for over a century. It was formed in 1877 and broken up on anti-trust grounds in 1983. Colloquially, the system was referred to as "Ma Bell," and it held a tight, vertical monopoly over telecommunication products and services in most areas of the United States and Canada.Â
