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GlossaryGlossaryGlossaryGlossary-4 August 2003 Access Navigator - Release 1.8
Glossary
Definitions
3DS0 Mode An ISDN BRI termination method that connects three DS0s to an ISDN BRI port,
one for each B and D channel. This mode is very simple but not as efficient as the
4:1 mode. It works with non-GR-303 switch interfaces, using fixed connections
for the B and D channels.
4:1 TDM Mode An ISDN BRI termination method that connects 2.25 DS0s to an ISDN BRI port,
one for each B channel and 0.25 for the D channel by multiplexing four D
channels onto one DS0. This mode can efficiently carry 4 BRI ports using only 9
DS0s. It works with GR-303 switch interfaces, using a fixed connection for the D
channel and dynamically connecting the two B channels when needed.
10Base-T The IEEE 802.3 standard for operating Ethernet local area networks (LANs) at 10
Mbps data rates. 10Base-T uses twisted-pair cabling (such as conventional phone
wires) to connect network elements to a wiring hub or router.
Alarm
Indication
Signal
AIS. Also known as a “Blue Alarm Signal” or “All Ones Keep Alive,” an AIS is
an unframed all ones bit pattern sent by equipment at the far end to indicate that
an alarm condition exists upstream in a circuit leading to the downstream
equipment. Keep-alive signals are required by the network facilities to prevent
oscillation of the line repeaters which causes interference (cross-talk and
bleeding) within adjacent channels.
Alternate Mark
Inversion
AMI. A line-encoding format used in bipolar DS1 (T1) transmission systems
whereby successive ones (marks) are alternately inverted in polarity. This is the
traditional method of line encoding used with voice signals. B8ZS coding is
preferred for data signals because AMI does not preclude long strings of zeros
from entering the public network from the DTE in violation of the pulse density
requirements mandated in Part 68 of the FCC Rules and AT&T Publication
62411.
Asymmetrical
Digital
Subscriber Line
ADSL. See description of Symmetrical Digital Subscriber Line (SDSL)
Attenuation Reduction of signal magnitude or increased signal loss, usually expressed in
decibels (dB).
Basic Rate
Interface
BRI. See Integrated Services Digital Network Basic Rate Interface.
Bellcore Bell Communications Research. See Telcordia.
Bipolar with
8-Zero
Substitution
B8ZS. A line-encoding format used to avoid long strings of zeros in a bipolar DS1
(T1) signals entering the network from the DTE. Every string of eight zeros is
replaced by a special code (token). The code contains a pattern of bipolar