Similar capacitors were used in the fourth-generation iPods. The first-generation iPod Shuffle uses a dual-transistor output stage ,  rather than a single capacitor-coupled output, and does not exhibit reduced bass response for any load. For all iPods released in and earlier, some equalizer EQ sound settings would distort the bass sound far too easily, even on undemanding songs.
From the fifth-generation iPod on, Apple introduced a user-configurable volume limit in response to concerns about hearing loss. Apple previously had to remove iPods from shelves in France for exceeding this legal limit. The units have been miniaturized over time. Originally, a FireWire connection to the host computer was used to update songs or recharge the battery. The battery could also be charged with a power adapter that was included with the first four generations. The third generation began including a pin dock connector , allowing for FireWire or USB connectivity.
This provided better compatibility with non-Apple machines, as most of them did not have FireWire ports at the time. As of the first-generation iPod Nano and the fifth-generation iPod Classic, Apple discontinued using FireWire for data transfer while still allowing for use of FireWire to charge the device in an attempt to reduce cost and form factor.
As of the second-generation iPod Touch and the fourth-generation iPod Nano, FireWire charging ability has been removed. The second-, third-, and fourth-generation iPod Shuffle uses a single 3. 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. The new connector replaces the older pin dock connector used by older iPods, iPhones, and iPads. Apple Lightning cables have pins on both sides of the plug so it can be inserted with either side facing up.
A large number are made by third party companies, although many, such as the iPod Hi-Fi , are made by Apple. Other notable accessories include external speakers, wireless remote controls, protective case, screen films, and wireless earphones.
BMW released the first iPod automobile interface,  allowing drivers of newer BMW vehicles to control an iPod using either the built-in steering wheel controls or the radio head-unit buttons.
Apple announced in that similar systems would be available for other vehicle brands, including Mercedes-Benz ,  Volvo ,  Nissan , Toyota ,  Alfa Romeo , Ferrari ,  Acura , Audi , Honda ,  Renault , Infiniti  and Volkswagen. Gecko Gear , founded in , sells accessories ranging from protective covers to cases, screen protectors to armbands.
Alternative connection methods include adapter kits that use the cassette deck or the CD changer port , audio input jacks, and FM transmitters such as the iTrip —although personal FM transmitters are illegal in some countries. Many car manufacturers have added audio input jacks as standard. The free service will allow passengers to power and charge an iPod, and view video and music libraries on individual seat-back displays. Please help improve this section by adding citations to reliable sources.
Unsourced material may be challenged and removed. MIDI files also cannot be played, but can be converted to audio files using the "Advanced" menu in iTunes. Alternative open-source audio formats, such as Ogg Vorbis and FLAC , are not supported without installing custom firmware onto an iPod e.
During installation, an iPod is associated with one host computer. Each time an iPod connects to its host computer, iTunes can synchronize entire music libraries or music playlists either automatically or manually. Song ratings can be set on an iPod and synchronized later to the iTunes library, and vice versa. A user can access, play, and add music on a second computer if an iPod is set to manual and not automatic sync, but anything added or edited will be reversed upon connecting and syncing with the main computer and its library.
If a user wishes to automatically sync music with another computer, an iPod's library will be entirely wiped and replaced with the other computer's library. Interface The signature iPod click wheel iPods with color displays use anti-aliased graphics and text, with sliding animations. The buttons perform basic functions such as menu, play, pause, next track, and previous track. Other operations, such as scrolling through menu items and controlling the volume, are performed by using the click wheel in a rotational manner.
The 3rd-generation iPod Shuffle does not have any controls on the actual player; instead it has a small control on the earphone cable, with volume-up and -down buttons and a single button for play and pause, next track, etc. The user interface for the iPod Touch is identical to that of the iPhone.
Differences include the lack of a phone application. Both devices use iOS. The store became the market leader soon after its launch  and Apple announced the sale of videos through the store on October 12, Full-length movies became available on September 12, Up to five authorized computers and an unlimited number of iPods could play the files.
The DRM could also be removed using third-party software. RealNetworks claims that Apple is creating problems for itself  by using FairPlay to lock users into using the iTunes Store. Steve Jobs stated that Apple makes little profit from song sales, although Apple uses the store to promote iPod sales.
Universal will now supply iTunes in an 'at will' capacity. This service allows users to access the Music Store from either an iPhone or an iPod Touch and download songs directly to the device that can be synced to the user's iTunes Library over a WiFi connection, or, in the case of an iPhone, the telephone network. The original iPod had the game Brick originally invented by Apple's co-founder Steve Wozniak included as an easter egg hidden feature; later firmware versions added it as a menu option.
Later revisions of the iPod added three more games: Parachute , Solitaire , and Music Quiz. In September , the iTunes Store began to offer additional games for purchase with the launch of iTunes 7 , compatible with the fifth generation iPod with iPod software 1. Elite Racing and Zuma. Additional games have since been added.
These games work on the 6th and 5th generation iPod Classic and the 5th and 4th generation iPod Nano. Even video game magazines like GamePro and EGM have reviewed and rated most of their games as of late. When unzipped, they reveal executable files along with common audio and image files, leading to the possibility of third party games. Apple has not publicly released a software development kit SDK for iPod-specific development.
File storage and transfer All iPods except for the iPod Touch can function in "disk mode" as mass storage devices to store data files  but this may not be the default behavior, and in the case of the iPod Touch, requires special software. The user must use software that has been specifically designed to transfer media files to iPods, so that the files are playable and viewable. Usually iTunes is used to transfer media to an iPod, though several alternative third-party applications are available on a number of different platforms.
Media files are stored on an iPod in a hidden folder, along with a proprietary database file. The hidden content can be accessed on the host operating system by enabling hidden files to be shown.
The media files can then be recovered manually by copying the files or folders off the iPod. Many third-party applications also allow easy copying of media files off of an iPod. Models and features While the suffix "Classic" was not introduced until the sixth generation, it has been applied here retroactively to all generic iPods for clarity.