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Home | Resources | Glossary | Communications - Glossary

Communications - Glossary

 

This glossary covers telecommunications terms and acronyms including company and
product specific terminology.

 
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2G
Second Generation
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3G
Third Generation
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3GPP
Third Generation Parnership Project (ETSI)
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AAL1
ATM Adaptation Layer, type 1
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AAL2
ATM adaptation layer type 2
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AAL5
ATM adaptation layer type 5
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AALn
ATM Adaptation Layer n. Methods associated with formatting information into ATM cells. AAL1 is used for real-time constant bit rate serices, AAL2 for real-time variable bit rate services and AAL5 for packetized data.
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ABIS
The interface between the BTS and the BSC within a GSM architecture, usually configured using a 16kbps slot structure
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ABR
Available Bit Rate
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Access Control
Network managers define access control by requiring authentication of the user's identity before permitting or limiting entry to a computer network or server.
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ACTS
Automated Computer Time System, a NIST service that provides announced time via telephone.
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ADM
Add-Drop Multiplexer
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ADSL
Asymmetric Digital Subscriber Line. ADSL delivers more bandwidth downstream (from CO to customer) than upstream and is largely used in cost-sensitive consumer applications. Compare against SHDSL, SDSL, HDSL and VDSL
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Advanced Encryption Standard (AES)
Developed by NIST and private companies, this standard is 256-bit based and thus presents a strong defense for sensitive material
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Aging
The systematic change in frequency of an oscillator with time.
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AIS
Alarm Indication Signal
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AM
Amplitude modulation (AM) is a method of impressing information onto a carrier waveform.
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AMI
Alternate Mark Inversion
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AMPS
Advanced Mobile Phone Service. A standard system for analog signal cellular telephone service in the US and other countries.
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ANSI
ANSI (American National Standards Institute) is the primary organization for fostering the development of technology standards in the United States.
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API
Application Program Interface. This interface allows software developers to write their software so that it can communicate with the computer's operating system or other programs.
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APON
ATM-Asynchronous Transfer Mode, Passive Optical Networking.
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ASCII
American Standards Code Information Interchange, a code in which alphanumeric characters are represented as eight-digit binary numbers.
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ATIS
Alliance for Telecommunications Industry Solutions
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ATM
Asynchronous Transfer Mode. A technique for packetizing infomration into fixed length cells. These cells are made up of 53 octets of which 5 comprise a 'header' and 48 carry information. ATM supports statistical multiplexing, allowing multiple cell-streams to share a transmission pipe efficiently.
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AuC
Authentication Center
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Authentication
Method by which a person is verified to be who they say they are, by password or other means.
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Authorization
Method by which an authenticated person is allowed certain access to the system, via password or other means.
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AV
Analog Video or Audio Visual
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B-ICI
Broadband Inter-Carrier Interface
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B-ISDN
Broadband Integrated Services Digital Network
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B8ZS
Bipolar with 8 Zero Substitution
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BCD
Binary Coded Decimal. Also called packed decimal, this is the representation of each digit of a decimal number by four-bit binary numbers. So the number 29 would be encoded as 0010 1001.
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BER
Bit Error Rate
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BIPM
The averaging and steering of TAI is done by the Bureau International des Poids et Mesures (BIPM).
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BITS
Building Integrated Timing Supply, also known as a Synchronization Supply Unit (SSU) or Stand Alone Synchronization Equipment (SASE).
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BootP
Bootstrap Protocol
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BPON, WDM
Wave Division Multiplexing, Passive Optical Networking.
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BPV
Bi-Polar Violation
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BRI
Basic Rate Interface. See ISDN
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BSC
Base Station Controller
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BSS
Base Station Subsystem
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BTS
Base Transceiver Station
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C2P
Circuit to Packet
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CA
Certificate Authority/Certification Authority. This type of organization or company issues certificates that state the authenticity of the parties involved in an exchange or agreement, much like a notary public. The certificate also contains keys and other security information.
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CAS
Channel Associated Signaling
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CBO
Cesium Beam Oscillator. A highly-precise frequency source. Also known as a cesium clock or cesium atomic standard.
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CBR
Constant Bit Rate
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CBT
Cesium Beam Tube. The key component of a cesium-based atomic clock.
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CC
Composite Clock
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CCITT
Consultative Committee for International Telegraph and Telephone. International organization repsonsible for the development of communications standards. Now called the ITU-T.
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CCS
Common Channel Signaling. Signaling system used in telephone networks that separates signaling information from user data.
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CCS7
Common Channel Signaling, version 7
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CD
Carrier Detect. A signal that indicates whether an interface is active. Also, a signal generated by a modem indicating that a call has been connected.
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CDMA
Code Division Multiple Access. A technique of multiplexing, also called direct sequence spread spectrum, in which bit streams are amplitude modulated onto pseudo-random chip streams.
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CDMA2000
3rd Generation Code Division Multiple Access
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CDSA
Common Data Security Architecture. This describes the security structure for the entire network. It is unique to each network because security is managed differently for each.
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CeNTU
Circuit emulation Network Termination Unit
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Certificate
Often called "digital certificates", this is a credential that includes security information and keys.
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Certificate Authority
Independent organization or vendor that acts as a notary, verifying the identification of involved parties, and issues certificates that contain identifying data.
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Certificate Extension
An extension of the X.509 standard that lets the certificate hold additional identifying information.
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Certificate Request Message
A certificate request message is composed of the certificate request along with other identifying data.
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Certification Path
A specified sequence of issued certificates necessary for the user to get their key.
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Certification Policy
This is how a CA defines its process for a user to obtain a certificate.
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Certification Revocation List
A CA maintains a list of certificates that have been cancelled but remain unused; revocation lists are vital when certificates have been stolen, for example.
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CES
Circuit Emulation Services
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CEV
Controlled Environment Vault
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chip
The carrier waveform in a DSSS is akin to a bit stream. Each 'bit' is called a chip to distinguish it from an information bit.
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CLE
Customer Located Equipment
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CLEC
Competitive Local Exchange Carrier
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Clock
Generator of frequencies which will be used to synchronize a network
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CMIP
Common Management Interface Protocol
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CMISE
Common Management Information Service Element
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CMTS
Cable Modem Termination System
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CN
Core Network
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CO
Central Office
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COFA
Change Of Frame Alignment
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Confidentiality
Keeping secret data from unauthorized eyes.
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Content Filtering
A filter that screens out data by checking, for example, URLs or key words.
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Coordinated Universal Time (UTC)
See UTC
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COTS
Commercial Off-The-Shelf. Products or services that are generally available and not built to customized specifications.
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cPCI
Compact Peripheral Component Interconnect - a bus standard
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CPE
Customer Premises Equipment
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CRC
Cyclic Redundancy Check
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Credential(s)
Much like a photo ID or birth certificate, electronic credentials (certificates) are recognized as proof of a party's identity and security level.
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CRM
See Certificate Request Message
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CRNC
Controlling RNC
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Cross-Certificate
Two or more CAs which issue certificates (cross-certificates) recognized in each others' domains.
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Cryptography
The method of encoding data so it can be accessed only by authorized individuals. See also: Encryption
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CSU
Customer Service Unit
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CSU/DSU
A CSU/DSU (Channel Service Unit/Data Service Unit) is a hardware device that converts a digital data frame from a local area network (LAN) into a frame appropriate to a wide-area network (WAN) and vice versa.
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CWDM
Coarse wave-division multiplexing. An alternative enterprise access method.
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CWTS
China Wireless Telecommunications Standard
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D-AMPS
Digital AMPS
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Data Encryption Standard (DES)
Encryption method in which both the sender and receiver of a message share a single key that decrypts the message.
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DCLS
Direct Current Level Shift, or digital IRIG.
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Decryption
The transformation of unintelligible data ("ciphertext") into original data ("clear text").
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Denial of Service
When a network is flooded with traffic, the systems cannot respond normally, so service is curtailed or denied. This is a favorite technique of network saboteurs.
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DES
Data Encryption Standard. Encryption method in which both the sender and receiver of a message share a single key that decrypts the message.
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DGPS
Differential Global Positioning System
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DHCP
Dynamic Host Configuration Protocol. Router or server software that assigns an IP address to each node in a network.
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Diffie-Hellman
A key-agreement algorithm used to create a random number that can be used as a key over an insecure channel.
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Digital Certificate
Digital Certificates are issued by a Certificate Authority, which verifies the identification of the sender. The certificate is attached to an electronic message, so the recipient knows the sender is really who they claim to be.
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Digital Fingerprint
Similar to digital signature, a digital fingerprint is the encryption of a message digest with a private key.
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Digital Signature
Like a digital certificate, a digital signature is verified by a Certificate Authority, and is attached to an electronic message so that it verifies that the sender is really who they claim to be. The difference between a digital certificate and a digital signature is found in how the message is encrypted and decrypted.
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Digital Signature Algorithm (DSA)
The asymmetric algorithm that is at the core of the digital signature standard.
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Digital Signature Standard (DSS)
A National Institute of Standards and Technology (NIST) standard for digital signatures, used to authenticate both a message and the signer. DSS has a security level comparable to RSA (Rivest-Shamir-Adleman) cryptography, having 1024-bit keys.
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Digital Time Stamp
See Time Stamp
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Directory
The directory is the storage area for network security information such as keys or server names.
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DLC
Digital Loop Carrier
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DOCSIS
Digital Subscriber Line Access Multiplexer
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DOS
Disk Operating System
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DPLL
Digital Phase-Locked Loop
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DPRAM
Dual Port RAM
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DS-n
Digital Signal at level n (e.g., DS-1, DS-3, etc.) used in the US and Japan
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DS0
Digital Signal, level 0
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DS1
Digital Signal, level 1
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DS2
Digital Signal, level 2
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DS3
Digital Signal, level 3
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DSA
Digital Signature Algorithm. DSA is a public-key method based on the discrete logarithm problem.
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DSLAM
A Digital Subscriber Line Access Multiplexer (DSLAM) is a network device, usually at a telephone company central office, that receives signals from multiple customer Digital Subscriber Line (DSL) connections and puts the signals on a high-speed backbone line using multiplexing techniques.
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DSS
Digital Signature Standard. A National Institute of Standards and Technology (NIST) standard for digital signatures, used to authenticate both a message and the signer. DSS has a security level comparable to RSA (Rivest-Shamir-Adleman) cryptography, having 1024-bit keys. DSA is the Digital Signature Standard.
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DSSS
Direct Sequence Spread Spectrum. See CDMA.
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DSU
Data Service Unit
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DSX-n
Digital Signal Cross-Connect level n
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DUS
Do not Use for Sync
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DWDM
Dense Wavelength Division Multiplexing
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DXC
Digital Cross Connect
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E-n
Digital Signal at level n (e.g., E-1, E-2. E-3, etc.) used in Europe
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E1
E1 (or E-1) is a European digital transmission format devised by the ITU-TS and given the name by the Conference of European Postal and Telecommunication Administration (CEPT). It's the equivalent of the North American T-carrier system format.
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E911
Enhanced 911. Specification that requires the ability to estabish the physical location of a mobile handset when transmitting to/from a wireless base station.
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EDGE
Enhanced Data rates for GSM Evolution
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EFM
Ethernet in the First Mile. General discussion surrounding the use of Ethernet prototol as the terminating technology to the home.
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EIR
Equipment Identity Register
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Element Manager (ENMTMS)
Software that manages the components of an application.
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EMC
Electro-Magnetic Compatibility
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EMI
Electro-Magnetic Interference
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Encryption
The transformation of clear data (clear text) into unintelligible data (ciphertext).
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ENMTMS
See Element Manager
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EOC
Embedded Operation Channels. Part of the SHDSL specification
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Ephemeris
Time obtained from observing the motion of the moon around the earth.
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EPON
Ethernet Passive Optical Networking.
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ESD
Electro-Static Discharge
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ESF
Extended Superframe Format
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ETSI
European Telecom Standards Institute
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Eurocard
European Packaging Specifications (IEC 60297, IEEE 1101.1, IEEE 1101.10, IEEE 1101.11)
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FCC
Federal Communications Commission - The US Government bureau responsible for regulating the communications industry
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FDD
Frequency Division Duplex
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FDL
Facility Data Link
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FDM
Frequency-division multiplexing (FDM) is a scheme in which numerous signals are combined for transmission on a single communications line or channel. Each signal is assigned a different frequency (subchannel) within the main channel.
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FDMA
Frequency Division Mutiple Access
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FIFO
First In First Out
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FIPS
Federal Information Processing Standards. These are a set of standards for document processing and for working within documents. Some commonly-used FIPS standards are 140-1, -2, -3, and -4, and 180.
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Firewall
Software and hardware systems that protect an internal network from outside data that could be harmful to the network, such as a virus sent via the Internet.
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FM
Fault Management
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FN
Fiber Node
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FTP
File Transfer Protocol
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FTTC
Fiber to the Curb. Using fiber transmission up to customer premises.
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FTTH
Fiber to the Home
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FWA
Fixed Wireless Access
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G.shdsl
See SHDSL
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Galileo
A satellite-based radio navigation system run by the European Space Administration (ESA), the European Commission and the European Organization for the Safety of Air Navigation. Using 27 satellites and three spares, Galileo is expected to be complete
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GDOP
Geometric Dilution of Precision
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GGSN
Gateway GPRS support node
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GHz
A GigaHertz is one billion (109) cycles per second
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GLONASS
Glonass is a Soviet space-based navigation system comparable to the American GPS system. The operational system contains 21 satellites in 3 orbital planes, with 3 on-orbit spares. Glonass provides 100 meters accuracy with its C/A (deliberately degraded) signals and 10-20 meter accuracy with its P (military) signals.
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GMT
Greenwich Mean Time, the mean solar time of the meridian of Greenwich, England. This was the primary basis for calculating standard time throughout the world until 1972 when it was superceded by UTC.
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GOS
Grade Of Service
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GPIB
General Purpose Interface Bus, IEEE 488
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GPRS
General Packet Radio Service
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GPS
Global Positioning System. Originally designated the NAVSTAR (Navigation System with Timing And Ranging) Global Positioning System, GPS was developed by the US Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces.
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GSM
GSM (Global System for Mobile communication) is a digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA).
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Hack/crack
"Hackers" are unauthorized programmers who write code that enables them to break into a computer network or program. "Crackers" are unauthorized programmers whose goal it is to break into computer networks or programs protected by security software or hardware.
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HAE
Host Application Equipment
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Hash
Also called "hash function" or hashing, used extensively in many encryption algorithms. Hashing transforms a string of characters usually into a shorter, fixed-length value or key.
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HDB3
High-Density Bipolar of order 3
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HDSL
High-data-rate Digital Subscriber Line. A DSL technology that delivers 1.544 Mbps each way (symmetrically) over two copper twisted pairs. Compare against SHDSL, SDSL, ADSL and VDSL
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HDT
Host Digital Terminal
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HE
Head-End
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HFC
Hybrid Fiber Coax (SMFCB)
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HLR
Home Location Register
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Holdover
When a clock that is locked to a PRS-traceable input loses that input, it enters a holdover mode where the frequency drift is related to the quality, or stratum level, of its oscillator.
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HSCSD
High Speed Circuit Switched Data
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HTML
HyperText Markup Language, the computer language used to create pages for the World Wide Web.
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HTTP
HyperText Transfer (or Transport) Protocol, the protocol most often used to transfer information from World Wide Web servers to users of the Web.
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Hz
Hertz. A measure of frequency relating to cycles per second.
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IAD
Integrated Access Device. CPE (customer premises equipment) that terminates xDSL, ISDN, T1 or other transmission protocol.
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Identity Certificate
The hash creates a message digest based on the contents of the message. The message is then encrypted using the publisher's private key, then it is appended to the original message.
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IEC
Inter-exchange Carrier
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IEEE
Institute of Electrical and Electronic Engineers, an international organization that sets standards for electrical and computer engineering.
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IETF
Internet Engineering Task Force, an international organization which sets standards for Internet protocols in their Request for Comment (RFC) papers.
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IKE
Internet Key Exchange, a security system that uses a private key and an exchange key that encrypts private keys. Passwords are delivered via the Internet.
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ILEC
Incumbent Local Exchange Carrier. Often referred to as the 'Baby Bells'.
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IMT-2000
International Mobile Telecommunications 2000
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IN
Intelligent Network
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In-band Authentication
When you use PKI for authentication, it is called in-band authentication. See also: out-of-band authentication.
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Integrity
Data that has retained its integrity has not been modified.
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IP
Internet Protocol
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IPSec
Internet Protocol Security describes the IETF protocols that protect the secure exchange of packets on the IP layer.
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IRIG
The InterRange Instrumentation Group is the IRIG standards steering committee. IRIG is a serial time format standard.
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Irrefutability
In the time security world, irrefutability means the source of the message cannot be disproved.
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ISA
Industry Standard Architecture; desktop PC adapter board specification
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ISDN
Integrated Services Digital Networks. There are two basic types of ISDN service: Basic Rate Interface (BRI) and Primary Rate Interface (PRI). BRI consists of two 64 kb/s B channels and one 16 kb/s D channel for a total of 144 kb/s. PRI is intended for users with greater capacity requirements. Typically the channel structure is 23 B channels plus one 64 kb/s D channel for a total of 1536 kb/s. In Europe, PRI consists of 30 B channels plus one 64 kb/s D channel for a total of 1984 kb/s.
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ITU
International Telecommunications Union, the international organization that sets standards for data communication.
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ITU-T
International Telecom Union -Telecom Standardization Sector
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Iu
Interface Between RNC and CN
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Iub
Interface Between Node B and RNC
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Iur
Interface between two RNCs
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IXC
Inter eXchange Carrier. A long distance telecomunications service provider.
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Jitter
Short-term variations of a timing signal from its ideal positions in time
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JTF
The Jitter Transfer Function (JTF) of a network element indicates the degree to which an output is affected by input jitter (i.e. amplified or attenuated)
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kbit
A kilobit is 1024 or 210 bits
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Key
An alphanumeric string that encrypts and decrypts data.
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Key Escrow
A secure storage maintained by a trusted third party, which holds keys.
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Key Generation
Creation of a key.
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Key Management
The process by which keys are created, authenticated, issued, distributed, stored, recovered, and revoked.
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Key Pair
An integrated pair of keys, one public, one private.
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Key Recovery
A method that allows messages to be decrypted even if the original key is lost.
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kHz
A kilohertz is 1000 cycles per second
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L1 Band, L2 Band
Each Navstar GPS satellite currently transmits in two dedicated frequency bands: L1 and L2, which are centered on 1575.42 and 1227.6 MHz respectively. L1 carries one encrypted signal, as does L2, both being reserved for the military. L1 also carries one unencrypted signal, for civilian use.
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LAN
Local Area Network
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LATA
Local Access and Transport Area - This was created by the 1984 divestiture and defines the geographic area over which the LEC may provide toll calls. The area is often smaller than that covered by a long distance area code.
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LCD
Liquid Crystal Display
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LDAP
The Lightweight Directory Access Protocol allows access to a directory service.
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Leap Second
The time error that accumulates between the earth's rotation and actual measured time is added (or deleted) as a leap second from UTC time on the last day of June or December in any year in which a leap second is needed to keep in step with the rotation of the earth.
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LEC
Local Exchange Carrier
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LED
Light Emitting Diode
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LMU
Location Management Unit. Equipment in a wireless base station that isolates the location of an individual handset.
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Local loop
The part of a telephone line which runs from a subscriber's premises to the telephone company's local exchange
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LORAN-C
LOng RAnge Navigation, version C. A long-range radio navigation position-fixing system consisting of an array of fixed stations that transmit precisely synchronized signals to mobile receivers.
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LOS
Loss Of Signal
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M12
Multiplexer/demultiplexer, DS1 to DS2
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M13
Multiplexer/demultiplexer, DS1 to DS3
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M23
Multiplexer/demultiplexer, DS2 to DS3
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MAC
A Message Authentication Code is a function that takes a variable length input and a key to produce a fixed-length output.
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MAN
Metropolitan Area Network
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Master clock
'A generator which generates an accurate frequency signal for the control of other generators'. Also known as a PRC.
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Mbit
Megabit
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Mbps
Megabits per second. One million bits transmitted each second.
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ME
Mobile Equipment
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Message Digest
The hash of a message. See also Hash.
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MHz
A MegaHertz is one million (1,000,000) cycles per second
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MIB
Management Information Base, a database on the network that tracks, records, and corrects performance for each device on the network.
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MIME
Multimedia Internet Mail Extensions
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MPLS
Multiprotocol Label Switching. A standards-approved technology for speeding up network traffic flow and making it easier to manage. Works with IP, ATM and frame relay.
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MS
Mobile Station
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MSC
Mobile Services switching Center
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MSO
Multisystem Operator. A cable service provider.
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MTBF
Mean Time Between Failure, a measure of reliability. The longer the time span between failures, the more reliable the device.
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MTIE
Maximum Time Interval Error
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MTTR
Mean Time To Repair
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Multiplexing
Process during which two or more signals are combined into one; at the other end, signals are "unbundled" by a demultiplexer. TDM is Time Division Multiplexing, FDM is Frequency Division Multiplexing, and CDMA is Code Division Multiple Access.
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Mxy
Muliplexer/demultiplexer, DSx to DSy (e.g. M12 is DS1 to DS2).
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NE
Network Element
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NEBS
Network Equipment Building Standard
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NEC
National Electrical Code
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Network Synchronization
A generic concept that depicts the way of distributing a common time and/or frequency to all elements in a network.
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NI
Network Interface
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NIST
National Institute of Standards and Technology, the National Measurement Institute in the United States. In the form of FIPS documents, NIST produces standards for security and cryptography.
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NIU
Network Interface Unit
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NLOS
Non-line-of-sight. A term referring to wireless services which don't require a clear open path between sites.
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NMA
Network Maintenance and Analysis (Bellcore)
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NMI
National Measurement Institute(s), the national authority in each country that is recognized as the source of official time.
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NMIServer
National Measurement Institute Server
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NMS
Network Management Software (or System)
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NNI
Network Node Interface
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NOC
A Network Operations Center monitors and manages a network's performance.
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Node B
UMTS base station
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Node Clock
A clock distributing synchronization information to one or more network elements
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Non-repudiatable
The Trusted Time time stamp has an audit trail back to its time source, during which the sender of the transaction is authenticated. Therefore, the sender cannot deny the time of the transaction.
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Notarization
Certification of the identity of the party in a transaction based on identifying credentials.
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ns
A nanosecond is one billionth (10-9) of a second
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NSS
Network Switching Subsystem
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NT1
Network Terminating equipment - type 1 (ISDN)
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NTMS
Network Time Management System
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NTP
Network Time Protocol provides a reliable way of transmitting and receiving time over TCP/IP networks and is useful for synchronizing the internal clock of computers to a common time source.
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OAM
Operations, Administration and Maintenance. Part of the ATM specification
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OAM&P
Operations, Administration, Maintenance & Provisioning
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OC-n
Optical Carrier level n (e.g., OC-1, OC-3, OC-9, OC-12, etc.)
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OCSP
Online Certificate Status Protocol, a method for validating digital certificates and signatures.
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OFDM
Orthogonal frequency-division multiplexing (OFDM) is a method of digital modulation in which a signal is split into several narrowband channels at different frequencies.
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OID
Object Identifier
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OLT
Optical Line Termination: a broadband multi-service device that controls the flow of information to and from all subscribers through the optical port.
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Online validation
A way of validating a key each time before it is used to verify that it has not expired or revoked.
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ONT
Optical Network Termination, used in fiber to the home (FTTH) to terminate the optical signal at the customer premise and provide the electrical interface to the customer equipment.
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ONU
Optical Network Unit
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OOF
Out Of Frame
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OPTXS
ATIS Optical Transport and Synchronization Committee (formerly T1X1)
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OS
Operating System
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OSF
Open Systems Foundation
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OSI
Open System Interconnect
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OSI
Operations System Interface
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OSMF
The Open Synchronization Media Framework (OSMF) is a protocol that gives telecom service providers the ability to remotely manage their synchronization networks and isolate synchronization related problems.
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OSS
Operational Support System
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Out-of-band Authentication
When authentication is performed using relatively insecure methods, such as over the telephone, it is called out-of-band authentication. In-band authentication, which uses PKI, is preferred. See In-band Authentication.
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PABX
A private automatic branch exchange (PABX) is an automatic telephone switching system within a private enterprise.
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Passive fiber splitters
devices that are approximately the size of a pen that allow the fiber to be split without a reduction in the bit rate.
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PBX
Private Branch Exchange
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PCI
Peripheral Component Interconnect, a local bus that supports high-speed connection with peripherals. It plugs into a PCI slot on the motherboard.
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PCISIG
PCI Special Interest Group
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PCM
Pulse Code Modulation
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PCS
Personal Communications Services
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PDA
Personal Digital Assistant
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PDH
Plesiochronous Digital Hierarchy
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PDOP
Position Dilution of Precision
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PICMG
PCI Industrial Computer Manufacturers Group
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PKCS
Public Key Cryptography Standards. These standards allow compatibility among different cryptographic products.
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PKI
Public Key Infrastructure. The PKI includes the Certificate Authority (CA), key directory, and management. Other components such as key recovery, and registration, may be included. The result is a form of cryptography in which each user has a public key and a private key. Messages are sent encrypted with the receiver's public key; the receiver decrypts them using the private key.
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PKIX
Extended Public Key Infrastructure, of PKI with additional features approved by the IETF.
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PLB
Private Label Branch
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PLL
Phase-Locked Loop
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PM
Performance Monitoring
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PMC
PCI Mezzanine Card
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Policy
A company's security policy.
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PON
Passive Optical Network
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POP
Point Of Presence
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POTS
Plain Old Telephone Service
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ppm
parts per million
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pps
Pulse per second
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PRC
Primary Reference Clock
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PRI
Primary Rate Interface. See ISDN.
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Primary Reference Source
Equipment that provides the highest quality sync for telecom networking as required by international standards. Typically derive source timing from GPS or CDMA signals or from stand-alone sources such as cesium.
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Private Key
This is a secret key, known to only of the parties involved in a transaction.
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PRN
Psuedo/Random Noise Code
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PRR
Primary Reference Receiver
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PRS
Primary Reference Source
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PSTN
Public Switched Telephone Network
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PTT
Post, Telephone and Telegraph. Government agency (largely outside North America) that provides both local and long distance telephone services.
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Public Key
Messages are sent encrypted with the recipient's public key, which is known to others; the recipient decrypts them using their private key.
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Public Key Certificate
Certificate in the form of data that holds a public key, authentication information, and private key information.
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PVC
Permanent Virtual Circuit
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PXI
PCI eXtensions for Instrumentation
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Qbus
Digital Equipment Corporation Bus
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QoE
Quality of Experience: a subjective term associated with the end user's perception of next generation services.
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QoS
Quality of Service. An expression of transmission error rates, often established by a network policy server.
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RA
A Registration Authority does not issue certificates, but does the required identification for certain certificate data.
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RAM
Random Access Memory
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RAN
Radio Access Network
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Resolution
Resolution of a time code refers to the smallest increment of time, whether it is days, hours, seconds, or other.
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Revocation
The withdrawing of a certificate by a Certificate Authority before its expiration date or time.
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Risk Management
The tasks and plans that help avoid security risk, and if security is breached, helps minimize damage.
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RJ-xx
In the U. S., telephone jacks are also known as registered jacks, sometimes described as RJ-XX, and are a series of telephone connection interfaces (receptacle and plug) that are registered with the U.S. Federal Communications Commission (FCC). RJ-11 is the designation for a common phone jack while RJ-45 is an Ethernet connection.
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RNC
Radio Network Controller for UMTS
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RSA
The RSA (Rivest-Shamir-Andleman) algorithm is used to create digital signatures.
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S/MIME
Secure Multipurpose Internet Mail Extensions. The standard for secure messaging.
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SA
Selective Availability (GPS accuracy limits for civilian users)
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SAASM
Selective Availability Anti-Spoofing Module
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SAN
Storage Area Network
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SASE
Stand-Alone Synchronization Equipment. See BITS.
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Sbus
Sun(TM) Bus
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SDA
Space, Defense and Avionics
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SDH
Synchronous Digital Hierarchy
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SDM
Service Delivery Management (SDM) is network management software that encompasses performance, fault and provisioning measurements.
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SDSL
Single-line Digital Subscriber Line. Non-standard method to deliver 1.544 Mbps (symmetric)over a single copper pair. Compare against SHDSL, HDSL, ADSL and VDSL
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SDV
Switch Digital Video (BMFB or BMFS)
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SEC
SDH Equipment Clock
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SF
Superframe Format
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SGSN
Serving GPRS support node
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SHA-1
Secure Hash Algorithm, which has a larger message digest, making it more secure against certain hacker attacks.
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SHDSL
Symmetric High-speed Digital Subscriber Line. A 2.3 Mbps ISO standard for transmission over one copper wire pair. Generally used for business applications. Compare against HDSL, SDSL, ADSL and VDSL
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Smart Card
A card the size of a credit card, which holds a microprocessor that stores information.
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SMC
SONET Minimum Clock
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SMTP
Simple Mail Transfer Protocol
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SNMP
Simple Network Management Protocol is the Internet standard protocol for network management software. It monitors devices on the network, and gathers device performance data for management information (data)bases ("MIB").
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SNR
Signal to Noise Ratio
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Solar Time
Time based on the revolution of the earth around the sun.
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SONET
Synchronous Optical NETwork
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SPE
Synchronous Payload Envelope
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SS7
Signaling System 7. Standard CCS system, developed by Bellcore, used with BISDN and ISDN.
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SSL
Secure Sockets Layer, a protocol that allows secure communications on the World Wide Web/Internet.
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SSL Client
Authentication Part of the SSL "handshake" process, when the client responds to server requests for a key.
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SSL Server
Authentication Part of the SSL "handshake" process, when the server informs the client of its certificate (and other) preferences.
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SSL-LDAP
Secure Sockets Layer-Lightweight Directory Access Protocol.
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SSM
Sync Status Messaging
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SSU
Synchronization Supply Unit. See BITS.
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STFP
Sbus Time & Frequency Processor
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STL
Studio-Transmitter Links
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STM-n
Synchronous Transport Module level n
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Stratum Level
The performance levels of frequency sources, or clocks, are classified in terms of stratum levels. Stratum 1, the highest, represents a source with an intrinsic accuracy of better than 1 x 10-11. Other levels defined are Stratum 2E, 2, 3E, 3 and 4 corresponding to lower levels of intrinsic accuracy.
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STS-n
Synchronous Transport Signal level n
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SVC
Switched Virtual Circuit
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SVN
Satellite Vehicle Number
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Sysplex Timer
The Sysplex Timer provides a synchronized Time-of-Day clock for multiple attached computers.
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T1
The T1 (or T-1) carrier is the most commonly used digital line in the United States, Canada, and Japan. In these countries, it carries 24 pulse code modulation (PCM) signals using time-division multiplexing (TDM) at an overall rate of 1.544 Mbps.
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TA
Technical Advisory
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TAI
International Atomic Time, (Temps Atomique International), results from the averaging and coordination of several hundred of the best atomic clocks around the world.
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TCCert
Time Calibration Certificate
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TCG
Time Code Generator
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TCP/IP
A mainstay of the Internet, the Transmission Control Protocol (TCP) provides dependable communication and multiplexing It is connection-oriented, meaning it requires a connection be established data transfer. It sits on top of the Internet Protocol (IP), which provides packet routing. This is connectionless, meaning each data packet has its source and destination data embedded, so it can bounce around a network and still get to its destination.
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TD-CDMA
Time Division-Code Multiple Access
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TDD
Time Division Duplex
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TDEV
Time DEViation
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TDM
Time-division multiplexing (TDM) is a method of putting multiple data streams in a single signal by organizing the composite signal into many segments, each having a very short duration. Each individual data stream is reassembled at the receiving end based on the timing.
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TDMA
Time Division Multiple Access
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TDOA
Time Difference of Arrival. A technique for triangulating on the location of a mobile handset from multiple wireless base stations. Used for E911 services.
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TDOP
Time Dilution of Precision
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Telnet
Telnet is a terminal emulation application protocol that enables a user to log in remotely across a TCP/IP network to any host supporting this protocol.
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TFP
Time & Frequency Processor
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TFTP
Trivial File Transfer Protocol
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TIE
Time Interval Error
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Time Stamp
A record mathematically linking a document to a time and date.
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Time Stamp Request
The client computer or application sends a time stamp request to the stamp server.
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Time Stamping Authority
A third party which provides authenticated time to the security process.
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TL1
Transaction Language 1
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TLS
Transport Layer Security, security that protects the OSI layer that is responsible for reliable end-to-end data transfer between end systems.
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TMN
Telecommunication Management Network
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TNM
Telecommunications Network Management (AT&T)
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Tool box
A group of software applications that have similar functions.
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TPC
Third Party Certificate. See Certificate.
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TPCA
Third Party Certification/Certificate Authority. See Certificate Authority.
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TR
Technical Reference
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Transaction
An activity, such as a request or an exchange.
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Triple-DES
Also called Triple Data Encryption Algorithm (TDEA) Data Encryption Standard is an algorithm that encrypts blocks of data.
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Trust
In the network security context, trust refers to privacy (the data is not viewable by unauthorized people), integrity (the data stays in its true form), non-repudiation (the publisher cannot say they did not send it), and authentication (the publisher--and recipient--are who they say they are).
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TSA
See Time Stamp Authority
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TSG
Timing Signal Generator. See BITS, SSU.
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TSR
See Time Stamp Request
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TSS
See Time StampServer
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TTL
Transmitter-Transmitter Links
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TVAR
Time VARiance
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UBR
Unassigned or Unknown Bit Rate
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UDP
User Datagram Protocol
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UDP/IP
User Datagram Protocol/Internet Protocol
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UE
User Equipment
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UI
Unit Interval (inverse of a signals' symbol rate)
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UMTS
Universal Mobile Telecommunications Service is a third-generation (3G) broadband, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to 2 Mbps
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USNO
U.S. Naval Observatory, in Washington, D.C., where the atomic clock that serves as the official source of time for the United States is maintained.
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UT1
The time scale derived from the earth's rotation - needed for celestial navigation and surveying
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UTC
The international time standard is called Universal Coordinated Time or, more commonly, UTC, for "Universal Time, Coordinated". This ITU standard has been in effect since 1972. UTC is maintained by the Bureau International de l'Heure (BIH) which forms the basis of a coordinated dissemination of standard frequencies and time signals.
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UTRAN
UMTS Terrestrial Radio Access Network
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Uu
UMTS air interface
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Vault
Secure data storage facility.
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VBR
Variable Bit Rate
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VCXO
Voltage -controlled Crystal Oscillator
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VDSL
Very-high-data-rate Digital Subscriber Line. High speed (13 to 52 Mbps) low range asymetric DSL technology. Compare against SHDSL, SDSL, ADSL and HDSL
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Verification
The process of making sure the identity of the parties involved in a transaction is what they claim it to be.
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VF
Voice Frequency
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ViiP
Video over IP. Similar to Voice over IP but typically at higher and constant bit rates (CBR).
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Virus
An unwanted program that hides "behind" legitimate code, and which is activated when the legitimate program is activated.
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VISA
Virtual Instrument Software Architecture
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VITA
VMEbus International Trade Association
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VLR
Visitor Location Register
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VME
Versa Module Europe; VMEbus specification governed by the VSO
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VOD
Video On Demand
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VoIP
Voice over IP. A set of facilities for managing the delivery of voice information over a packet-switched network.
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VPN
Virtual Private Network, a way that authorized individuals can gain secure access to an organization's intranet, usually via the Internet.
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VPP
VXI Plug & Play Specification
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VSO
VITA Standards Organization
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VT
Virtual Tributary (for SONET systems)
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VXCO
Voltage-controlled Crystal Oscillator
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VXI
VME Extensions for Instrumentation
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W3C
Based at the Massachusetts Institute of Technology (MIT), this international organization creates standards for the World Wide Web.
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WAN
Wide Area Network
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WAP
Wireless Application Protocol, a worldwide standard for applications used on wireless communication networks.
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WCDMA
Wide-band Code Division Multiplex Access
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WML
Wireless Markup Language. An HTML-equivalent for low-bandwidth and/or small screen format wireless phones and PDAs
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WPKI
Wireless Public Key Infrastructure.
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WTLS
Wireless Transport Layer Security
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WWW
World Wide Web
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X.509
The ITU's X.509 standard defines a standard format for digital certificates, the most-widely used PKI standard.
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X.509 v3 Certificate Extension
The X.509 standard with extended features approved by the IETF.
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xDSL
Generic name for the various types of DSL service. See ADSL, HDSL, SDSL, SHDSL and VDSL.
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