ARCnet
A network developed by DataPoint. Originally proprietary, by the late 1980s it was no longer proprietary and had about as large a market share as
Ethernet among small businesses. It was almost as fast and was considerably cheaper at the time.
BNC
A connector for coaxial cable such as that used for some
video connections and RG58 "cheapernet" connections. A BNC connector has a bayonet-type shell with two small knobs on the female connector which lock into spiral slots in the male connector when it
is twisted on. Different sources expand BNC as Bayonet Navy Connector, British Naval Connector, Bayonet Neill Concelman, or Bayonet Nut Connection.
Communications port
A connector for a communications interface, usually, a serial port.
Daisy chain
A bus wiring scheme in which,
for example, device A is wired to device B, device B is wired to device C, etc. The last device is normally wired to a resistor or terminator. All devices may receive identical signals or, in contrast to a simple
bus, each device in the chain may modify one or more signals before passing them on.
DIN
Deutsche Institut fuer Normung. The German standardization body, a
member of ISO.
DIN-8
An 8-pin round connector, sometimes used for RS-232 serial communication when space is restricted, such as on laptop computers.
Dorito Syndrome
Feelings of emptiness and dissatisfaction triggered by addictive substances that lack nutritional content. "I just spent six hours surfing the
Web, and now I've got a bad case of Dorito Syndrome."
Enhanced Graphics Adapter
(EGA) An IBM PC display standard with a resolution of 640 x 350
pixels of 16 colors.
Enhanced IDE
A enhanced version of the IDE hard disk standard capable of transfer rates up to 7 Mbytes/second.
Enhanced parallel port
(EPP) A parallel port that confirms to the IEEE's EPP standard. An EPP is actually an expansion bus that can handle 64 disk drives and other peripherals.
Jumper
A removable wire or small plug whose presence or absence is used to determine some aspect of hardware configuration.
Multiscan
A monitor that can synchronize to a variety of horizontal scan rates and refresh rates, allowing it to display images at different resolutions.
Multisync
An NEC trademark term for multiscan. As NEC was the first to manufacture multiscan monitors the term is often used interchangeably with multiscan.
Network
Hardware and software data communication systems. The ISO seven layer model attempts to provide a way of partitioning any computer network into independent modules from the
lowest (physical) layer to the highest (application) layer. Many different specifications exist at each of these layers. Networks are often also classified according to their geographical extent: local area network
(LAN), metropolitan area network (MAN), wide area network (WAN) and also according to the protocols used.
Null modem
A cable, especially an RS-232 cable, for
connecting serial ports on two computers directly, rather than via modems. Since, according to the specification, both computers should transmit on pin three of their RS-232 connectors and receive on pin two, a null
modem cable needs to connect one computer's pin two to the other's pin three and vice versa. It also needs to have male connectors at both ends (again, according to the specification).
Pin-out
(Or "pinout") The allocation of logical functions or signals to the electrical connection points (pins) of an integrated circuit or other component or connector.
Plenum cable
Cable that that can be (legally) installed in the plenum (the space between a ceiling and the floor above it). Such cable is (usually) Teflon-coated
so that it will not give off toxic fumes when burned. In some parts of the world such cable is required by law.
Printer port
A connector found on many
microcomputers intended for attaching a printer. This may be a general-purpose input/output parallel port or may be a special Centronics interface. Most printers can also be connected to a serial port but that is
unlikely to be described as a "printer port".
Serial port
(Or "com port") A connector on a computer to which you can attach a
serial line connected to peripherals which communicate using a serial (bit-stream) protocol. The most common type of serial port is a 25-pin D-type connector carrying RS-232 signals. Smaller connectors (e.g.
9-pin D-type) carrying a subset of RS-232 are often used on personal computers. The serial port is usually connected to an integrated circuit called a UART which handles the conversion between serial and parallel
data.
Super Video Graphics Array
(SVGA) A video display standard created by VESA for IBM PC compatible personal computers. The resolution is 800 x 600 4-bit
pixels. Each pixel can therefore be one of 16 colors.
Terminator
A resistor connected to a signal wire in a bus or network for the purpose of impedance matching
to prevent reflections. For example, a 50 ohm resistor connected across the end of an Ethernet cable. SCSI chains and some LocalTalk wiring schemes also require terminators.
Token ring
A computer local area network arbitration scheme in which conflicts in the transmission of messages are avoided by the granting of "tokens" which give permission
to send. A station keeps the token while transmitting a message, if it has a message to transmit, and then passes it on to the next station. Often, "Token Ring" is used to refer to the IEEE 802.5 token
ring standard, which is the most common type of token ring.
Twisted pair
A type of cable in which pairs of conductors are twisted together to randomize possible
cross-talk from nearby wiring. Inadequate twisting is detectable using modern cable testing instruments.
