Question

1 main line on telephone

Answer 1

Telephone is the source to communicate.

Hope it helps......

Answer 2

A landline telephone (also known as land line, land-line, main line, home phone, landline, fixed-line, and wireline) is a phone that uses a metal wire or optical fiber telephone line for transmission as distinguished from a mobile cellular line, which uses radio waves for transmission.[1] In 2003, the CIA World Factbook reported approximately 1.263 billion main telephone lines worldwide. China had more than any other country at 350 million and the United States was second with 268 million. The United Kingdom had 23.7 million residential fixed home phones.[2]