Conn. Gen. Stat. § 12-439
Payment of tax. Penalties for nonpayment.
(b) Payment of any tax hereunder may be made by bank draft, check or money order, or in such other form or manner as suits the convenience of the taxpayer, provided no payment shall operate to discharge any taxpayer from liability for any tax imposed by this chapter except to the extent to which such payment is made in lawful money of the United States or in a form that in regular course of business can be converted thereinto. In the case of any invalid payment, every recourse of the state for the collection of the amount of such tax, as herein authorized, shall continue to be available, and further penalties shall accrue as though such invalid payment had not been made, and the commissioner may thereafter determine the manner of making subsequent payments by the taxpayer concerned. The commissioner shall issue his receipt to any taxpayer for any payment upon request. He shall deposit daily all receipts with the State Treasurer. Such deposit shall operate as a full discharge of the commissioner of all liability therefor.
See Sec. 4-32 re state revenue accounting procedure.