Mass. Gen. Laws ch. 166, § 15A: Entitlement to hand sets as station equipment

Section 15A. A telephone company, upon request therefor by a subscriber who has paid to such company, for a period of not less than thirty-six months, an extra charge for the use of a hand telephone set, so called, furnished to him by such company, in lieu of a wall or desk set, shall continue to furnish, or furnish, to such subscriber such a set as station equipment without extra charge therefor.