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Appendix D
Glossary
10BASE5 -
Also called thick Ethernet, 10BASE5 is a 10 Mhz, Baseband, 500
meter coaxial segment. The cable is also refered to as "yellow" cable. Cable
impedance is 50
Ω
. Thick Ethernet cable is typically used as a trunk or backbone
path of the network.
10BASE2 -
Also called thin net or CheaperNet, 10BASE2 is a 10 Mhz, Baseband,
185 meter coaxial segment. Cable impedance is 50
Ω
.
AUI -
The Attachment Unit Interface is the cable connection from an MAU
(transceiver) to a DTE (typically a workstation) consisting of a 15 conductor
twisted pair cable of 50 meters maximum length.
BNC SERIES -
A 10BASE2 thin coax connector with push-on bayonet locking
lug that quickly locks into place with a half twist.
COAX SEGMENT -
A segment of Ethernet cable that contains a MAU.
15 PIN D CONNECTOR -
The AUl cable uses 15 pin D-connectors. D refers to
the shape of the connector shell. Also called miniature D, DB-15, or DIX
connectors.
DIX CONNECTOR -
see D CONNECTORS.
DTE -
Data Terminal Equipment is connected to the MAU with an AUI cable. The
DTE could be a Ethernet workstation, repeater, or bridge.
HEARTBEAT -
see SQE
IMPEDANCE -
Impedance is an electrical characteristic of a circuit dealing
with the combination of the AC and DC resistance and the appearance of that
resistance to attached circuits.
JABBER -
The jabber function is the MAUs ability to automatically inhibit the
transmit data from reaching the medium if the transmit data time length exceeds
150 ms. duration. This protects the medium from being overrun with data packets
from a possibly defective device.
JITTER -
Jitter is the fluctuation of the data packet in respect to a standard
clock cycle. Jitter is undesirable and must be minimized.
SQE -
Signal Quality Error test, commonly refered to as heartbeat is a special
802.3 signal sent by the MAU to the DTE indicating that a multiple transmission
(which is illegal) has occured.
