A state agency and its officers and employees may not buy, rent, or pay toll charges for a telephone for which the telephone number is not listed or available from directory assistance to the general public unless the unlisted telephone number is used:
(1) to provide access to computers, telephone system control centers, long-distance networks, elevator control systems, and other tone-controlled devices for which restricted access to the telephone number is justified for security or other purposes;
(2) in narcotics undercover operations;
(3) in the detection of illegal sales of securities; or
(4) in the investigation of motor fuels tax fraud.