Rev 1600 contains the rules governing the Communications Services Tax (CST), RSA 82-A. This proposal implements the changes in Chapter 346:252-258 of the Laws of 2019, concerning the applicability of the CST to prepaid wireless telecommunications and voice over Internet protocol (VoIP) services. Rev 1601.15, Rev 1601.21, Rev 1601.22, and Rev 1601.24, respectively, are being adopted to define “prepaid wireless telecommunications service,” “retail transaction,” “seller,” and “VoIP.” Rev 1601.19 defining “retailers” is being readopted with amendments as Rev 1601.20 to explicitly include prepaid wireless telecommunications and VoIP services among the communications services sold by retailers. Rev 1605 is being adopted to specify the sourcing rules for prepaid wireless telecommunications and VoIP services.