Indiana Code Title 6. Taxation § 6-2.5-12-11

Sec. 11. As used in this chapter, “prepaid calling service” means the right to access exclusively telecommunications services, which must be paid for in advance and which enables the origination of calls using an access number or authorization code, whether manually or electronically dialed, and that is sold in predetermined units or dollars of which the number declines with use in a known amount.