Telecommunications Service Provider

A telecommunications service provider (TSP) is a type of communications service provider that has traditionally provided telephone and similar services. This category includes incumbent local exchange carriers, competitive local exchange carriers, and mobile wireless communication companies.

While some people use the terms "telecom service provider" and "communications service provider" interchangeably, the term TSP generally excludes Internet service providers (ISPs), cable companies, satellite TV, and managed service providers.

TSPs provide access to telephone and related communications services. In the past, most TSPs were government owned and operated in most countries, due to the nature of capital expenditure involved in it. But today there are many private players in most regions of the world, and even most of the government owned companies have been privatized.

...
Wikipedia