Section 1. A telegraph or telephone company shall not commence the construction of its line until three fourths of its capital stock have been unconditionally subscribed for, and at least one half has been paid in in cash; and the directors shall, within ten days after commencing construction, file in the office of the state secretary a sworn statement of such subscription and payment. For the purposes of sections 1 to 10, inclusive, the word ”company” shall not include a municipal lighting plant or cooperative which operates a telecommunications system pursuant to section 47E of chapter 164.