sentences:  In 1984, Sunil Mittal started assembling push-button phones in India, which he earlier used to import from a Taiwan company, Kingtel, replacing the old fashioned, bulky rotary phones that were in use in the country then.Bharti Telecom Limited (BTL) was incorporated and entered into a technical tie up with Siemens AG of Germany for manufacture of electronic push button phones.By the early 1990s, Bharti was making fax machines, cordless phones and other telecom gear.