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A/D
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Analog to digintal conversion
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ADPCM
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Adaptive differential pulse code modulation
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AIS
|
Alarm indication signal; a signal transmitted in lieu of the normal
signal to maintain transmission continuity, and indicates to the
receiving terminal that there is a transmission fault located
upstream or at the transmitting terminal
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ALBO
|
Automatic line build out
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AMI
|
Alternate mark inversion
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ANSI
|
American National Standards Institute
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APS
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Automatic protection switch
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ASPR
|
Automatic span powering repeater
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AWG
|
American wire gauge
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B8ZS
|
Bipolar eight zero substitution; a line coding scheme to substitute
000 + - 0 - + for 00000000 if the preceding pulse was +, and 000 - +
0 + - for 00000000 if the preceding pulse was -. Done to maintain
ones density
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BER
|
Bit error rate
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BERT
|
Bit error rate test
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BOC
|
Bell Operating Company
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bps
|
Bits per second1
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BPV
|
Bipolar violation; the detection of any isolated error, whether it
deletes a pulse or adds a pulse
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CCC
|
1Clear channel capability; allows unrestricted data bearing any
number of consecutive zeros to pass through a transmission facility.
This usually requires B8ZS line coding on all elements
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CO
|
Central office; of a telephone company; the location of the
switching center
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CODEC
|
Coder-decoder; converts analog voice to digital and vice-versa
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CPE
|
Customer premises equipment
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CRC
|
Cyclic Redundancy Check; a method of detecting the existence of
errors in the transmission of a digital signal using polynomial
division
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CSU
|
Channel Service Unit; the interface from CPE to the public T-1 line
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D4
|
Fourth generation digital channel bank
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DACS
|
Digital access and cross-connect system; a digital switching device
for routing T-1 lines and possibly DS-0 portions of lines, among
multiple T-1 ports
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dB
|
Decibel
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dBdsx
|
Decibels with respect to the standard level at the DSX-1
cross-connect
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DC
|
Direct current; battery power
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DLC
|
Digital loop carrier
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DS-0
|
Digital signal, level 0; 64 kilobits per second, the international
standard rate for digitized voice channels
|
|
DS-1
|
Digital signal, level 1; 1.544 megabits per second, the North
American standard
|
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DS-3
|
Digital signal, level 3; 44.736 megabits per second, the North
American standard
|
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DSU
|
Digital service unit; converts RS232, RS422, or V.35 terminal
interface data to DSX-1 interface
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DSX-1
|
Digital service cross connect, level 1; part of the DS-1
specification
|
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DTMF
|
Dual tone multi-frequency; TOUCHTONE dialing, as opposed to rotary
dialing
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E&M
|
Signaling leads on a voice tie line; known as Ear and Mouth
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|
ESF
|
Extended Super Frame, a DS-1 framing format of 24 frames. In this
format, 2 Kbps are used for framing pattern sequence, 4 Kbps are
used for the Facility Data Link, and the remaining 2 Kbps are used
for CRC
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|
FB
|
Framing bit
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FCC
|
Federal Communcations Commission
|
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FDL
|
Facility data link; an embedded overhead channel within the ESF
format
|
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FEC
|
Forward error correction
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|
Hz
|
Hertz, cycles per second
|
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ISDN
|
Integrated Services Digital Network
|
|
IXC
|
Interexchange carrier; a long distance telephone company (not a LEC)
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|
kA
|
Kiloamperes
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kHz
|
Kilohertz, thousands of cycles per second
|
|
LATA
|
Local access and transport area
|
|
LEC
|
Local exchange carrier
|
|
M24
|
Multiplexer that converts one DS-1 line to 24 voice channels for a
C.O.
|
|
M44
|
Multiplexer that converts one T-1 of 44 ADPCM channels into two T-1s
with PCM encoding
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|
mA
|
Milliamperes
|
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MHz
|
Megahertz
|
|
Mux
|
Multiplexer
|
|
NI
|
Network interface; demarcation point between the public network and
CPE
|
|
NIU
|
Network interface unit; the unit installed at the demarcation which
provides loopback test capabilities
|
|
OOF
|
Out of frame
|
|
OOS
|
Out of synchronization or else out of service
|
|
PAM
|
Pulse amplitude modulation
|
|
PBX
|
Private branch exchange; a private telephone switching system
|
|
PCM
|
Pulse code modulation
|
|
pF
|
Picofarads, a measure of capacitance PIC Polyethylene insulated
conductor
|
|
PL
|
Private line; a leased line, not switched
|
|
POP
|
Point of presence; termination of long distance line from a long
distance carrier at a central office
|
|
POTS
|
Plain old telephone service
|
|
PSTN
|
Public switched telecommunications network
|
|
QRSS
|
Quasi random signal sequence
|
|
RBOC
|
Regional Bell Operating Company
|
|
RZ
|
Return to zero; DS-1 signals pause at zero voltage between each
pulse when making zero crossings
|
|
SLC
|
Subscriber loop carrier
|
|
SF
|
Superframe Format; a DS-1 framing format of 12 frames
|
|
T1
|
A 1.544 Mbps transmission standard
|
|
T-BERD
|
A tradename for T1 bit error rate tester made by TTC
|
|
TDM
|
Time division multiplexer
|
|
TSI
|
Time slot interchange; a method of temporarily storing data bytes so
they can be sent in a different order than received; a way to switch
|
|
VF
|
Voice frequency
|
|
VG
|
Voice grade; the common analog telephone line
|
|
VMR
|
Violation monitor removal; a function which removes all violations
which are detected so that they do not propagate along the span line
|
|
ZBTSI
|
Zero Byte Time Slot Interchange; a method of providing Clear Channel
Capability without using B8ZS. This was an interim solution
advocated by Verilink
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