Which act regulates the storage of telephone calls and electronic data transmissions?

The correct choice is the Electronic Communications Privacy Act (ECPA). This act specifically addresses the privacy of electronic communications, which includes both telephone calls and data transmissions. Enacted in 1986, the ECPA established provisions to protect the confidentiality of communications while in transit and during storage by service providers. It aims to safeguard against unauthorized interception and disclosure of electronic communications, representing a key legal framework for regulating how these types of information are stored and accessed.

In contrast, HIPAA focuses primarily on the protection of personal health information, while PCI-DSS is a standard designed to enhance the security of payment card transactions. The Data Protection Act, which can vary by jurisdiction, generally pertains to the processing of personal data but does not specifically set rules around the storage of electronic communications in the same manner as the ECPA does.