Context: The dock connector also allowed the iPod to connect to accessories, which often supplement the iPod's music, video, and photo playback. Apple sells a few accessories, such as the now-discontinued iPod Hi-Fi, but most are manufactured by third parties such as Belkin and Griffin. Some peripherals use their own interface, while others use the iPod's own screen. Because the dock connector is a proprietary interface, the implementation of the interface requires paying royalties to Apple.

Question: Which iPod accessory was made by Apple but is no longer produced?
Answer: iPod Hi-Fi

Question: What are two companies that make iPod accessories?
Answer: Belkin and Griffin

Question: What part of the iPod is needed to communicate with peripherals?
Answer: dock connector

Question: What is the condition for third parties using the dock connector?
Answer: paying royalties

Question: The majority of peripherals for iPod are produced by what kinds of companies?
Answer: third parties

Question: What's the name of the now-discontinued accessory manufactured by Apple, that connected via the iPod's dock connector?
Answer: iPod Hi-Fi