The third generation began including a 30-pin dock connector, allowing for <answer>FireWire</answer> or USB connectivity. This provided better compatibility with non-Apple machines, as most of them did not have <answer>FireWire</answer> ports at the time. Eventually Apple began shipping iPods with USB cables instead of <answer>FireWire</answer>, although the latter was available separately. As of the first-generation iPod Nano and the fifth-generation iPod Classic, Apple discontinued using <answer>FireWire</answer> for data transfer (while still allowing for use of <answer>FireWire</answer> 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, <answer>FireWire</answer> charging ability has been removed. The second-, third-, and fourth-generation iPod Shuffle uses a single 3.5 mm minijack phone connector which acts as both a headphone jack and a data port for the dock.
What interface was gradually phased out for both charging and data transfer?
FireWire