Three standards of information/instruction manipulation/execution.
The navi is comparable in size to today's PDA and appears in as many aesthetic variations as ballpoint pens do today. The key to the miniaturization of information-processing devices was the introduction of virtual interface. Even after carbon nanotube technology made it possible to manufacture tiny "computers", the want of a large screen, stereo speakers, and full-size input devices kept portable computers in the realm of sidekicks to one's desktop or notebook. However, as soon as it was possible to project a crisp display to a size larger than the device that created it, the Navi caught on big time and computers as we know them today were rendered unnecessary.
A navi has both digital and quantum processing units working in tandem; This is what distinguishes it from a computer. Computers take binary data and perform binary operations on them; Navis are exponentially more powerful. The idea of waiting for your device to finish processing something or configuring your printer drivers is absurd. The electronic microprocessor takes care of simple number crunching tasks, while the quantum nanoprocessor takes care of things like understanding your voice in a crowded subway station or finding you a good place to stop for dinner.
The navi fulfills the role of today's personal computer and portable entertainment and communications devices. It can also interface with other Navis, Neon, and Neptune. Its screen can typically project itself out to a size of between one and twenty inches. It is typically controlled by voice command, though it also includes neural link, optical scanning, and manual input hardware(stylus input is popular).
Neon is the environmental system built into most modern buildings and vehicles and installed at certain key locations outdoors. Neon can be roughly compared to today's Internet. Typically, each building has a distinct Neon address, and when your navi wants to talk to your cousin's navi in a different part of town, the nearest Neon hub will accept the signal and send it along a series of other Neon hubs until it reaches the one nearest your cousin, at which point the signal is transmitted to her navi. Neon is the duct tape that connects navis, Neptune devices, and people.
Neptune is the standard by which non-computing devices communicate with navis and Neon. When Neon tells the lights to dim, it does so by means of the Neptune protocol. When you buy something at a vending machine, it uses Neptune code to send an "update balance" message to the nearest Neon hub and subsequently to your bank account. Neptune devices have only digital processing capabilities.