Which technology is used to transmit voice calls over digital data lines?

The technology that is used to transmit voice calls over digital data lines is Voice over IP (VoIP). VoIP converts analog voice signals into digital data that can be transmitted via the internet or other digital communication networks. This allows users to make voice calls using an internet connection rather than traditional phone lines. VoIP technology can facilitate various communication forms, such as voice calls, video calls, and messaging, all utilizing the same infrastructure, which allows for more flexible and often more cost-effective communication options.

Wi-Fi, while it can provide the wireless connectivity needed for VoIP to work, is not the technology that specifically enables the transmission of voice calls. Cloud computing refers to storing and accessing data and applications over the internet rather than on a local computer, which is not directly related to the transmission of voice calls. Streaming involves delivering data in a continuous flow and is typically associated with media content rather than voice communication alone. Thus, VoIP stands out as the correct choice for transmitting voice calls over digital data lines.