Control-C else, typically returning control to the user. Ctrl-C was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing, with Ctrl-Z (Undo), Ctrl-X (Cut), Ctrl-V (Paste), and Ctrl-P (Print). The first four letters are all located together at the left end of the bottom row of the standard QWERTY keyboard, and P towards the upper right. The equivalent key combination on Macintosh computers is Command-C. Control-C as an abort command was popularized by TOPS-20 and TOPS-10 and adopted by other systems including Unix. It was also adopted by Digital Equipment operating
Projection keyboard a light source and may project a full size QWERTY keyboard. The projected keyboard size is usually 295 mm x 95 mm and it is projected at a distance of 60 mm from the virtual keyboard unit. The projection keyboard detects up to 400 characters per minute. Projection keyboards connect to the computer either through Bluetooth or USB. Bluetooth dongle technology enables the projection keyboard for point to multi-point connectivity with other Bluetooth devices, such as PCs, PDAs and mobile phone. The way that Bluetooth projection keyboards connect to devices depends on the specific tablet, phone or computer. Apart from