Conn. Gen. Stat. § 5-260

Upon request of any state employee who is a member of any organization which includes among its members at least three hundred state employees and which functions at least in part to serve the economic or professional interest of such state employee members, the Comptroller shall deduct from such employee's salary his dues as such a member and shall remit the amounts so deducted to the treasurer of the organization designated by the employee in such request. Such deduction may be discontinued upon written request thirty days in advance.