Which of the following is NOT a use of USB?

The use of USB (Universal Serial Bus) primarily revolves around connecting devices to a computer or to each other for data transfer, power supply, or both. In this context, connecting a keyboard, connecting external hard drives, and connecting a printer are all common uses of USB technology.

Connecting a keyboard involves utilizing a USB port to interface the keyboard with the computer for input purposes. For external hard drives, USB serves as a means of transferring data between the drive and the computer, as well as supplying power to the drive in many cases. Similarly, connecting a printer via USB enables data transmission from the computer to the printer for printing documents.

On the other hand, transmitting voice calls over a telephone is not a function that USB is designed for. While USB can facilitate certain types of communication, such as connecting a headset for voice interaction with a computer or using VoIP applications, traditional voice calls handled over a telephone line do not utilize USB technology. Therefore, the option related to transmitting voice calls over a telephone stands apart from the legitimate uses of USB.