As you type, the processor in the keyboard analyzes the key matrix and determines what characters to send to the computer. It maintains these characters in its memory buffer and then sends the data.
Many
laptop keyboard connect to the computer through a cable with a PS/2 or USB connector. Laptops use internal connectors. Regardless of which type of connector is used, the cable must carry power to the
laptop keyboard, and it must carry signals from the laptop keyboard back to the computer.
Wireless keyboards, on the other hand, connect to the computer through infrared (IR), radio frequency (RF) or Bluetooth connections. IR and RF connections are similar to what you'd find in a remote control. Regardless of which sort of signal they use, wireless keyboards require a receiver, either built in or plugged in to the USB port, to communicate with the computer. Since they don't have a physical connection to the computer, wireless keyboards have an AC power connection or use batteries for power.
Whether it's through a cable or wireless, the signal from the keyboard is monitored by the laptop keyboard controller. This is an integrated circuit that processes all of the data that comes from the keyboard and forwards it to the operating system. When the operating system is notified that there is data from the keyboard, it checks to see if the keyboard data is a system level command.
The application determines whether the
laptop keyboard data is a command, like Alt-f, which opens the File menu in a Windows application. If the data is not a command, the application accepts it as content, which can be anything from typing a document to entering a URL to performing a calculation. If the current application does not accept keyboard data, it simply ignores the information.
