Until December 31, 1997, a tax is imposed upon the act or privilege of originating or receiving intrastate telecommunications by a person in this State at the rate of 5% of the gross charge for such telecommunications purchased at retail from a retailer by such person. Beginning January 1, 1998, a tax is imposed upon the act or privilege of originating in this State or receiving in this State intrastate telecommunications by a person in this State at the rate of 7% of the gross charge for such telecommunications purchased at retail from a retailer by such person. However, such tax is not imposed on the act or privilege to the extent such act or privilege may not, under the Constitution and statutes of the United States, be made the subject of taxation by the State. Beginning January 1, 2001, prepaid telephone calling arrangements shall not be considered telecommunications subject to the tax imposed under this Act.