either using the optical or analog minijack output or alternatively a USB port delivering digital audio output using a more expensive USB+Mini DisplayPort hybrid adapter.

Optical audio output is used to link Macs to home theater setups and A/V systems capable of multi-channel surround sound, by way of a mini TOSlink adapter ... "audio line out (digital/analog)".

According to AppleInsider, Apple’s new 13-inch MacBrook Pro does not have support for optical digital audio output that was ... where you can use a physical adapter if you want, or do wireless ...

Turtle Beach, a pioneer in digital audio and gaming headphone technology, today announced the latest addition to its Audio Advantage product line, the Amigo II and Micro II USB audio adapters ... adds ...