Keyboard Cable

The keyboard cable is the long cable that runs between the main case of the keyboard, and the connector that attaches to the rest of the system. The cable itself is typically of round cross-section and about 1/8th of an inch in diameter, and really, not that exciting. :^) It normally contains within it four wires, corresponding to the four signal lines used for interfacing to the PC through the keyboard connector. These are enclosed in a fairly thick cover of some sort of PVC or plastic.

Detail of a typical keyboard cable. The four colored wires carry
power and data signals to and from the keyboard. The thin metal
wires form a braid that surrounds the other wires to shield them
from interference. A PVC jacket surrounds the cable.

Most keyboards come with a cable that is several feet long, which is sufficient to reach the connection point of most PCs from the user's work area. However, sometimes the cable is not long enough to reach some tower PCs that are placed on the floor next to the desk where the keyboard is. This happens especially with keyboard cables that are partially coiled--they may reach if you stretch them, but the tension from the coils in the wire may make you feel like someone is constantly trying to yank the keyboard away from you. ;^) If you find that this is the case, you can buy an inexpensive (under ten dollar) keyboard cable extender to let you position your PC and keyboard where you want them for your convenience. See here for more.

The only real quality and design issues when it comes to the keyboard cable are probably related to its attachment points. The cable itself is pretty tough and will last for ages unless abused. The problems usually occur due to stress at the points where the cable attaches to either the keyboard case, or the keyboard connector. The attachment point to the case is especially troublesome for some keyboards, which cause the cable to come out from the front of the keyboard perpendicular to the width of the keyboard. If the keyboard is then pushed up against something, the cable can become pinched, bending at close to a 90-degree angle. This often results in damage over a period of time, resulting in intermittent problems when the keyboard (or the cable) is moved.

The connection point of a keyboard cable within a typical keyboard.
The keyboard cable terminates in a connector that attaches to the
internal circuit board, visible at the bottom left of the photo. Note the
way the cable is wound around three plastic posts--this reduces the
chances that a yank on the cable will pull it loose from the internal circuitry,
or cause it to be damaged (though that can certainly still happen.)