Which peripheral port is NOT mentioned as necessary for connecting a mixer to a computer?

The selection of Thunderbolt as the peripheral port that is not mentioned as necessary for connecting a mixer to a computer is accurate because Thunderbolt, while a high-speed data transfer technology that can be used for audio interfaces, is not universally necessary or commonly referenced for basic audio mixing connections in practice.

In contrast, USB, Firewire, and Ethernet are more standard connections typically found in audio equipment. USB is widely recognized for its compatibility with various mixers and computers for both data transfer and power. Firewire, albeit less common in recent models, has historically been used for higher-bandwidth audio connections. Ethernet can be used for digital audio networking and is increasingly popular for networking audio devices, especially in professional environments.

Therefore, while Thunderbolt is a powerful option, the other ports are more directly related to traditional connections in the context of audio mixing.