Glossary J-L0-A | B | C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
0-A | B
| C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
- Jabber: Network error caused
by an interface card continually sending corrupted data onto the
- Jacket: The outer protective covering of wire or
- JAVA: An object oriented programming language developed by Sun
Microsystems. Used on the World Wide Web.
- Jitter: The slight movement
of a transmission signal in time or phase that can introduce errors & loss of
synchronization in high speed synchronous communications.
- Jumper: A
short length of conductor used to make temporary connection between terminals,
around a break in a circuit, or around an instrument.
- K: Kilo
notation for one thousand or & Expression for one kilobyte standard quantity
measurement for disk & diskette storage & semiconductor circuit capacity; one K
of memory equals 1024 bytes (8-bit characters) of computer memory; slightly
more than a thousand.
- Kbps: See Kilobits per
- KEV: 1000 electron volts.
- Kilo: Prefix meaning
- Kilobits per second: (Kbps) The measurement of
data rate & transmission capacity.
- KPSI: Tensile strength in
thousands of pounds per square inch.
- KW: Kilowatt or 1000
- Kynar: PVDF Polyvinylideneneflouride resin manufactured by the
Pennwallt Corporation. A crystalline, high molecular weight polymer of PVCDF
having high dielectric strength as well as abrasion resistant
- L: Symbol for inductance.
- LAN: See Local Area Network
- LAN Manager: Microsoft's network
operating system based on OS/2.
- LAN Server: IBM's implementation of
- LANaware: Applications that have file & record locking
for use on a network.
- LANignorant: Applications written for single
users only. These are not recommended for use on LAN's.
Application written for client-server networks.
- LAP: See Link Access Protocol
- LAPD: See Link
- LASER: (Light Amplification by Stimulated
Emission of Radiation) A coherent source of light with a narrow beam & a narrow
spectral bandwidth (about 2nm)
- LAT: DECnet protocol governing
communications between terminals & hosts.
- Latency: The time interval
between when a network station seeks access to a transmission channel & when
access is granted or received; equivalent to waiting time.
Pertaining to wire & cable, the axial distance required for one cabled
conductor or conductor strand to complete one revolution about the axis around
which it is cabled.
- Lay Direction: The twist in the cable as
indicated by the top strands while looking along the axis of cable away from
the observer. Described as "right hand" or "left hand."
- Layer: A
conceptual level of network processing functions defined by OSI. Processing is
though to take place in layers starting form the physical transmission of data
up through to the commands of an end-user.
- LDM: (Limited Distance
Modem) See Line Driver
- Lead: A wire, with or
without terminals, that connects two points in a circuit.
The undesirable passage of current of the surface of or through an
- Learning Bridge: A bridge which automatically "learns" the
topology of the LAN addresses of each node as it receives packets. Learning
bridges require little or no setup at the time of installation.
line: A private telephone line reserved for the leasing customer's
- LED: See Light-Emitting
- Level: A measurement of the difference between a quantity
or value & an established reference.
- Light Source (Fiber Optic): An
object capable of emitting light, In fiber optics, the light source is normally
an LED or laser.
- Light-Emitting Diode: (LED). A
semi-conductor light source that emits visible light or invisible infrared
- Limited Distance Modem: (LDM) See Line
- Line Conditioning: The addition of equipment to improve
("tune") the transmission characteristics of a dedicated voice grade telephone
line. Conditioning is done to increase data speed (bit rate) & reduce bit error
- Line Connection: The process of terminating the communications
links between DTE's. The term is also used for the first phase of the data
transfer sequence. Line Disconnection: The process of terminating the
communications link between two DTEs. Opposite of Line Connection.
- Line Driver: A DCE device that amplifies a data signal for
transmission over cable for distances beyond the RS232 limit of 50 feet, even
up to several miles. Also called "limited-distance modem" (LDM) or "short haul
- Line Equalizer: A reactance (inductance and/or
capacitance) connected in series with a transmission line to alter the
frequency-response characteristics of the line.
- Line Level: The
amplitude of a signal at a certain point on a transmission line. Usually
expressed in decibels.
- Line Noise: Noise originating in the
transmission media. The term is normally used for telephone lines. A certain
amount of line noise is practically unavoidable.
- Line Speed:
Expressed in Bps, the maximum rate at which data can reliably be transmitted
over a line using given hardware.
- Line Turnaround: The reversal of
transmission direction between two communicating DTEs. Line turnaround is a
major source of inefficiency in high-speed, half-duplex data
- Link: A telecommunications circuit or
- Link Access Procedure-D: (LAPD) Link
level protocol devised for ISDN connections, differing from LAPB (Lap-Balanced)
in its framing sequence. Likely to be used as basis for LAPM, the proposed
CCITT modem error control standard.
- Link Access
Protocol: (LAP) AppleTalk protocols including ELAP for Ethernet & LLAP for
- Link Layer: See Data Link
- LLC: See Logical Link
- Load: A device that consumes power from a source & uses
that power to perform a function.
- Loaded Line: A telephone line
equipped with loading oils; adds inductance to minimize amplitude
- Lobe: The cable that runs between a MAU & a device
(workstation, peripheral or processor).
- Local Area
Network: (LAN) A high speed method of transmitting information between
mainframe, mini- & micro- computers. Most often installed in a limited area
such as an office building or small campus.
- Local Line, Local Loop: A
channel connecting the subscribers equipment to the line-terminating equipment
in the central office. Usually a metallic circuit (either 2-wire or
- LocalTalk: A 230 kilobits per second baseband network using
the CSMA/CA access method.
- Logical Link Control:
(LLC) Defined by IEEE 802 standards as the upper sublayer of the data link
layer. It allows higher-layer protocol to operate independently of the LAN
- Logical Unit 6.2: (LU 6.2) An IBM
protocol suite governing peer-to-peer communications in an SNA (Systems Network
- Long Link: A Parallel Extender manufactured by
- Loopback: A diagnostic test in which a signal is
transmitted across a medium while the sending device waits for its
- Loosely Coupled: A multiprocessor computer in which the CPU's
(Central Processing Units) have separate memory & system buses.
Reduction in signal strength, expressed in decibels; also, attenuation;
opposite of gain.
- LU 6.2: See Logical Unit