User`s guide

G-6 DL600E E1 Data Multiplexer UserÕs Guide
H
HDB3 (High Density Bipolar 3)Ñ A bipolar coding method that does not
allow more than 3 consecutive zeroes. A
T1 carrier standard, like D4, ESF.
I
impedance ÑResistance to the ßow of alternating current in a circuit. A
DSU/CSU is used to amplify and match impedance or match/balance net-
work signaling to the customer's equipment
IP address
ÑA unique, 32-bit identiÞer for a TCP/IP host on a network. IP
addresses are normally printed in dotted decimal form, such as
L
LED (Light emitting diode)ÑA device that accepts electrical signals and con-
verts the energy to a light signal.
loopbackÑA diagnostic test in which the transmitted signal is returned to the
sending device after passing through a data communications link or network.
This allows a technician (or built-in diagnostic circuit) to compare the
returned signal with the transmitted signal and get some sense of what's
wrong.
LOS (Loss of Signal)ÑOccurs when an input signal is detected as all zeros
for 176 bit times.
lossÑA reduction in signal strength, expressed in decibels.
LT (Local Test)ÑA data port signal to DSU/CSU.
M
maskÑRefer to subnet mask.
MIB (Management Information Base)ÑA structure that deÞnes what is
obtainable from a network device and what can be controlled. The
MIB pro-
vides a directory listing the logical names of all information resources residing
in the network and pertinent to the network's management. It is used to
describe network management variables.
MTBF (Mean Time between Failure)ÑThe average time a manufacturer esti-
mates before a failure occurs in a component, a printed circuit board or a
complete telephone
system.