What type of connector is commonly found on a sound card for legacy devices?

The correct choice is DB-15, which refers to a type of connector commonly used for legacy devices, particularly in relation to audio applications. The DB-15 connector is also known as a 15-pin D-sub connector and was frequently utilized in older systems for connecting various peripherals, including certain types of audio equipment such as MIDI devices and legacy surround sound systems.

This type of connector provides multiple pins capable of carrying different signals, which is especially important for audio applications where multiple channels or control signals may be required. As technology has advanced, newer connector types have emerged, but DB-15 remains relevant for compatibility with older devices.

Other connector types mentioned are not typically associated with sound cards for legacy devices. USB is a universal connection for various peripherals, but it is more modern and not specifically for legacy sound systems. DB-9, often used for serial connections, primarily connects devices such as modems and mice. HDMI is a high-definition multimedia interface designed for newer audio and video devices, and it is not common in legacy setups.