Accessibility the ability of a lightning plug to be inserted in either direction reduces wear from attempts to insert the plug upside down, and offers user convenience. Power capacity lightning improves on micro-usb's (before usb 3.0) Limit of 9 watts, allowing at least 12 watts to accommodate the iPad. Directionality the lightning port can either charge a device, or allow the device to power accessories. The optional supplement usb on-the-go allows usb devices to do this lightning is an eight-pin connector which carries a digital signal. It is non-directional and can be inserted into the device with either side facing up or down. Apple offers various adapters between the lightning and other interfaces such as lightning to apple proprietary 30 pin, lightning to universal serial bus (usb) as well as accessories to interface with high-definition televisions, vga monitors, secure digital (sd) cards and sd card reader. The lightning to 30-pin adapter supports only a limited subset of the available 30 pin signals: usb data, usb charging, and analog audio output. Official lightning connectors contain an authentication chip that makes it difficult for third-party manufacturers to produce compatible accessories without being approved by apple.
