Wireless Access Point (WAP)

The internet cable running through a wall is fast and stable. But a smartphone or tablet has no port to plug a cable into. If you want to move around and use the internet freely, you need radio waves.

That's where a wireless access point comes in. Plug it into the end of the cable, and it builds a bridge through the air. It converts the electrical signal in the cable into radio waves (Wi-Fi signals) and sends them out in every direction.

It works in reverse, too. When your device sends wireless data, the AP catches it with its antenna and converts it back into a wired signal. In other words, it acts as a wireless on-ramp that connects the wired highway to the wireless skyway.

Thanks to this, you can carry your phone anywhere in a room and get online with no tangle of cables.

The boxy Wi-Fi router you use at home is a combo device. It packs several machines into one: a router (which decides where data goes between your devices and the internet, and also hands out an address to each device), a switch (which gives you several Ethernet ports), and an AP function (which sends out the wireless signal).

To be more precise, a standalone wireless access point doesn't hand out addresses or direct traffic. It focuses only on one job: turning a wired signal into radio waves to extend your connection range.

Business-grade APs in particular are designed from the start for places where lots of people connect at once, with dedicated wireless chips and antennas. When several APs share the users between them, even a big environment doesn't bog down easily.

So at home, one all-in-one router is usually enough. But in a school or office with hundreds of people, dozens of dedicated APs are mounted on the ceilings, connected through switches to a main router.

One router alone can't cover a large building full of concrete walls. Radio waves get weaker every time they pass through a wall, and speed drops sharply as distance grows.

Placing APs in hallways and rooms, with their locations and channels carefully planned, greatly reduces the problem. If APs are too close together, they interfere with each other and can actually slow things down. Because all the APs connect to one wired network, you can cover the whole building with a wireless network that has few dead zones.

You can even stay online while walking around. When your signal weakens, your phone switches to an AP with a better signal, a seamless Wi-Fi roaming feature. Your phone decides when to switch, so some devices cling to a weak signal for a long time.

That's why you can take a video call while walking from the first floor to the top floor of a big office tower or hospital, and on a well-designed network it will rarely drop.