Conn. Gen. Stat. § 36a-784
Whenever any sales finance company or retail seller renews or extends the installments remaining unpaid so that the retail installment contract is both extended beyond its original date of final payment and the installments are reduced or increased in amount, such renewal or extension agreement shall be in writing. Such sales finance company or retail seller may, any law to the contrary notwithstanding, make or collect a total additional charge therefor not exceeding an amount equivalent to a true rate of interest of twelve per cent per annum on the respective descending balances computed from the date of the oldest unpaid installment existing prior to such renewal or extension. When the renewal or extension does not include both an extension beyond the original date of final payment and a reduction or increase in the amount of the installments, such sales finance company or retail seller may make a total additional charge therefor up to the maximum lawful contract rate of interest permitted under the laws of this state but not exceeding twelve per cent true interest per annum, on the payment or payments extended for the period or periods of the extension.
Conn. Gen. Stat. § 36a-784
(1949 Rev., S. 6702.)
See Sec. 42a-9-203 re attachment and enforceability of security interests.