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Troubleshooting Wireless Networks
Direct Outward Dialing (DOD)
Direct Outward Dialing (DOD) is a service of a local phone company (or local exchange carrier) that allows subscribers within a company's private branch exchange (PBX) system to connect to outside lines directly. Continue Reading
MILNET
MILNET was the name given to the part of ARPANET, the forerunner of the Internet, that was designated for nonclassified U.S. military use. Continue Reading
Manchester encoding
In data transmission, Manchester encoding is a form of digital encoding in which data bits are represented by transitions from one logical state to the other. Continue Reading
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Telecommunications Display Device (TDD)
A Telecommunications Display Device (TDD), also known as a text telephone, is a telephone equipped with a keyboard and a display for people who are hearing- or speech-impaired. Continue Reading
Toslink
Toslink is a connector format for fiber optic digital audio cables. Continue Reading
file transfer
File transfer is the movement of one or more files from one location to another.Continue Reading
Cisco Certified Network Professional (CCNP)
Cisco Certified Network Professional (CCNP) is an intermediate-level certification in the Cisco certified professional program.Continue Reading
non-geographic number
A non-geographic number, also called a virtual number, is a telephone number associated with a country, but not to any single geographic location within that country.Continue Reading
QAM (quadrature amplitude modulation)
QAM (quadrature amplitude modulation) is a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth.Continue Reading
Network Service Access Point (NSAP)
The Network Service Access Point (NSAP) is one of two types of hierarchical addresses (the other type is the network entity title) used to implement Open Systems Interconnection (OSI) network layer addressing.Continue Reading
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Source-route transparent (SRT) bridging
Source-route transparent (SRT) bridging is a bridging scheme developed by IBM that combines source-route bridging (SRB) and transparent bridging in the same network.Continue Reading
reverse Telnet (direct Telnet)
Reverse Telnet (sometimes called direct Telnet) is the initiation of a Telnet session from a computer system to one of its remote users.Continue Reading
passive FTP
Passive FTP (sometimes referred to as PASV FTP because it involves the FTP PASV command) is a more secure form of data transfer in which the flow of data is set up and initiated by the File Transfer Program (FTP) client rather than by the FTP server...Continue Reading
anti-replay protocol
The anti-replay protocol is part of the Internet Engineering Task Force (IETF) Internet Protocol Security (IPSec) standard.Continue Reading
MAC address (Media Access Control address)
In a local area network (LAN) or other network, the MAC (Media Access Control) address is your computer's unique hardware number.Continue Reading
megahertz (MHz)
The megahertz, abbreviated MHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one million hertz (1,000,000 Hz).Continue Reading
shielded twisted pair
This definition closely duplicates the definition for twisted pair.Continue Reading
data link control (DLC)
DLC also is an abbreviation for digital loop carrier.Continue Reading
HDSL (High bit-rate Digital Subscriber Line)
Also see our Fast guide to DSL. HDSL (High bit-rate Digital Subscriber Line), one of the earliest forms of DSL, is used for wideband digital transmission within a corporate site and between the telephone company and a customer.Continue Reading
connection
In telecommunication and computing in general, a connection is the successful completion of necessary arrangements so that two or more parties (for example, people or programs) can communicate at a long distance.Continue Reading
Personal Access Communications System (PACS)
Personal Access Communications System (PACS) is a type of wireless telephone network compatible with telephone sets, answering machines, fax machines, and computers.Continue Reading
crossover cable
A crossover cable is a cable that is used to interconnect two computers by "crossing over" (reversing) their respective pin contacts.Continue Reading
Evernet
The term Evernet has been used to describe the convergence of wireless, broadband, and Internet telephony technologies that will result in the ability to be continuously connected to the Web anywhere using virtually any information device.Continue Reading
satellite Internet connection
A satellite Internet connection is an arrangement in which the upstream (outgoing) and the downstream (incoming) data are sent from, and arrive at, a computer through a satellite.Continue Reading
cable modem termination system (CMTS)
A cable modem termination system (CMTS) is a component that exchanges digital signals with cable modems on a cable network.Continue Reading
fast retransmit and recovery (FRR)
In TCP/IP, fast retransmit and recovery (FRR) is a congestion control algorithm that makes it possible to quickly recover lost data packets.Continue Reading
transactional e-mail
Transactional e-mail is a type of Web-based marketing in which e-mail recipients can buy goods and services directly from an e-mail message, without being redirected to the retailer's Web site.Continue Reading
phantom dialing
In mobile wireless communication, phantom dialing is a term used to describe what occurs when a user unintentionally presses a pre-programmed auto-dial number on their cellular telephone keypad and unintentionally initiates a phone call.Continue Reading
satellite return Internet connection
A satellite return Internet connection is an arrangement in which incoming data arrives at your computer from a satellite downlink and outgoing data (such as your request for the next Web page) is sent over a regular telephone line.Continue Reading
terbo
The suffix terbo appears in the V.32terbo modem protocol and indicates the third version of the V.32 protocol.Continue Reading
media access management
In the Open Systems Interconnection (OSI) communication reference model, media access management is performed by the Media Access Control (MAC) sublayer of the Data-Link Layer.Continue Reading
registered port numbers
The registered port numbers are the port numbers that companies and other users register with the Internet Corporation for Assigned Names and Numbers (ICANN) for use by the applications that communicate using the Internet's Transmission Control ...Continue Reading
cable head-end
A cable head-end (or headend) is the facility at a local cable TV office that originates and communicates cable TV services and cable modem services to subscribers.Continue Reading
spatial division multiple access (SDMA)
Also see frequency division multiple access (FDMA) and time division multiple access (TDMA).Continue Reading
10BASE-F
10BASE-F, one of several physical media specified by IEEE 802.3, is the use of optical fiber in an Ethernet local area network (LAN).Continue Reading
visitor-based networking (VBN)
Visitor-based networking (VBN) is the provision of high-speed Internet access for mobile PC users in need of temporary service in public places.Continue Reading
network interface unit (NIU or Network Interface Device)
A network interface unit (NIU) (sometimes called a network interface device) is a device that serves as a common interfacefor various other devices within a local area network (LAN), or as an interface to allow networked computers to connect to an ...Continue Reading
balun
A balun is a device that joins a balanced line (one that has two conductors, with equal currents in opposite directions, such as a twisted pair cable) to an unbalanced line (one that has just one conductor and a ground, such as a coaxial cable).Continue Reading
lambda switching (photonic switching, or wavelength switching)
Lambda switching (sometimes called photonic switching, or wavelength switching) is the technology used in optical networking to switch individual wavelengths of light onto separate paths for specific routing of information.Continue Reading
telephone jacks
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).Continue Reading
ETSI (European Telecommunications Standards Institute)
The European Telecommunications Standards Institute (ETSI) is a non-profit organization that establishes telecommunications standards for Europe.Continue Reading
D-channel
In the Integrated Services Digital Network (ISDN), the D-channel is the channel that carries control and signalling information.Continue Reading
High-Speed Circuit-Switched Data (HSCSD)
High-Speed Circuit-Switched Data (HSCSD) is circuit-switched wireless data transmission for mobile users at data rates up to 38.4 Kbps, four times faster than the standard data rates of the Global System for Mobile (GSM) communication standard in ...Continue Reading
whois
whois is a program that will tell you the owner of any second-level domain name who has registered it with Verisign (or with Network Solutions, which was acquired by Verisign).Continue Reading
X server
An X server is a server of connections to X terminals in a distributed network that uses the X Window System.Continue Reading
root directory
In a computer file system that is organized as a hierarchy or tree, the root directory is the directory that includes all other directories.Continue Reading
10BASE-36
10BASE-36 is a type of physical cabling defined in the IEEE 802.3 (Ethernet) standard for broadband application.Continue Reading
DECT (Digital Enhanced Cordless Telecommunications)
Unlike the analog cordless phones you may have in your home, DECT (Digital Enhanced Cordless Telecommunications) is a digital wireless telephone technology that is expected to make cordless phones much more common in both businesses and homes in the...Continue Reading
Transmeta
Transmeta is a Silicon Valley start-up company known for its recruitment of high profile talent and its Crusoe chip, designed for mobile Internet computing.Continue Reading
well-known port numbers
The well-known port numbers are the port numbers that are reserved for assignment by the Internet Corporation for Assigned Names and Numbers (ICANN) for use by the application end points that communicate using the Internet's Transmission Control ...Continue Reading
10BASE-2
10BASE-2, one of several physical media specified by IEEE 802.3 for use in an Ethernet local area network (LAN), consists of Thinwire coaxial cable with a maximum segment length of 185 meters.Continue Reading
10BASE-5
10BASE-5, one of several physical media specified by IEEE 802.3 for use in an Ethernet local area network (LAN), consists of Thickwire coaxial cable with a maximum segment length of 500 meters.Continue Reading
DARPA (Defense Advanced Research Projects Agency)
DARPA (Defense Advanced Research Projects Agency) is the independent research branch of the U.S. Department of Defense that funded a project that in time was to lead to the creation of the Internet.Continue Reading
DOCSIS (Data Over Cable Service Interface Specifications)
Now known as CableLabs Certified Cable Modems, DOCSIS (Data Over Cable Service Interface Specifications) is a standard interface for cable modems, the devices that handle incoming and outgoing data signals between a cable TV operator and a personal ...Continue Reading
Primary Rate Interface (PRI)
In the Integrated Services Digital Network (ISDN), there are two levels of service: the Basic Rate Interface (BRI), intended for the home and small enterprise, and the Primary Rate Interface (PRI), for larger users.Continue Reading
symmetric communications
Compare asymmetric communications.Continue Reading
phase-shift keying (PSK)
Phase-shift keying (PSK) is a method of digital communication in which the phase of a transmitted signal is varied to convey information.Continue Reading
ACTA (America's Carriers Telecommunications Association)
ACTA (America's Carriers Telecommunications Association) is a lobbying organization for over 165 small long-distance telephone carrier companies.Continue Reading
softswitch
Softswitch (software switch) is a generic term for any open application program interface (API) software used to bridge a public switched telephone network (PSTN) and Voice over Internet Protocol (VOiP) by separating the call control functions of a ...Continue Reading
value-added network (VAN)
A value-added network (VAN) is a private network provider (sometimes called a turnkey communications line) that is hired by a company to facilitate electronic data interchange (EDI) or provide other network services.Continue Reading
small form factor (SFF)
Small form factor (SFF) refers to any of several physically compact connector designs that have been developed for use in fiber optic systems.Continue Reading
metropolitan area network (MAN)
A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network...Continue Reading
small form-factor pluggable (SFP)
Small form-factor pluggable (SFP) is a specification for a new generation of optical modular transceivers.Continue Reading
infranet
The infranet is a proposed universal, public, packet-switched supplement to the Internet for businesses and high-demand private users that would provide guaranteed security, reliability, and quality of service (QoS).Continue Reading
hybrid fiber coaxial network (HFC network)
A hybrid fiber coaxial (HFC) network is a telecommunication technology in which optical fiber cable and coaxial cable are used in different portions of a network to carry broadband content (such as video, data, and voice).Continue Reading
moonbounce or Earth-Moon-Earth (EME)
Moonbounce, also called Earth-Moon-Earth (EME), is a form of wireless communication in which the moon is used as a passive satellite.Continue Reading
Basic Rate Interface (BRI)
In the Integrated Services Digital Network (ISDN), there are two levels of service: the Basic Rate Interface (BRI), intended for the home and small enterprise, and the Primary Rate Interface (PRI), for larger users.Continue Reading
gigahertz (GHz)
The gigahertz, abbreviated GHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one thousand million hertz (1,000,000,000 Hz).Continue Reading
subnetwork
A subnetwork is a separately identifiable part of a larger network that typically represents a certain limited number of host computers, the hosts in a building or geographic area, or the hosts on an individual local area network.Continue Reading
Veronica
Veronica is a program that allowed you to search the files of the Internet's Gopher servers for a particular search string.Continue Reading
Home Phoneline Networking Alliance (HPNA)
The HPNA (Home Phoneline Networking Alliance) is an industry group that promotes standards for using existing phone lines and jacks to interconnect computers within a home.Continue Reading
ferrule
A ferrule (from Latin viriola, meaning little bracelet) is a ring or cap attached to an object to protect against damage, splitting, or wear.Continue Reading
egress
Egress (pronounced EE-grehs, from Latin egressus, or going out) is the act of going out of something.Continue Reading
U interface
In Integrated Services Digital Network (ISDN) Basic Rate Interface service, a U interface is the electrical interface for the single twisted pair wire connection from a local phone company (the central office) to a home or business.Continue Reading
V.xx
The V Series Recommendations from the ITU-TS are summarized in the table below.Continue Reading
vampire tap
A vampire tap is a connection to a coaxial cable in which a hole is drilled through the outer shield of the cable so that a clamp can be connected to the inner conductor of the cable.Continue Reading
OC-768
OC-768 is currently the fastest synchronous optical network (SONET) standard rate for data transmission on optical fiber as part of the broadband ISDN (BISDN).Continue Reading
T1 (T-1)
Also see the T-carrier system, of which the T1 is a part.Continue Reading
netsplit
In using an Internet Relay Chat (IRC) network, a netsplit is the loss of contact between two IRC servers.Continue Reading
media attachment unit (MAU)
MAU is also sometimes used as the abbreviation for the token ring network multistation access unit (MSAU).Continue Reading
local access and transport area (LATA)
LATA (local access and transport area) is a term in the U.S. for a geographic area covered by one or more local telephone companies, which are legally referred to as local exchange carriers (LECs).Continue Reading
EtherExpress
EtherExpress is a technology from Intel that is used in network server adapters (devices that attach the server to the network cable) for Ethernet-based local area networks (LANs).Continue Reading
iNet
An iNet (pronounced AI-neht) is any network that uses the Internet Protocol (IP).Continue Reading
text on nine keys (T9)
Text on nine keys (T9) is a system that lets fixed and mobile phone users send text messages by pressing a number key for each letter in the message -- effectively making a keyboard out of the nine numeric phone entry keys.Continue Reading
RS-232C
RS-232C is a long-established standard ("C" is the current version) that describes the physical interface and protocol for relatively low-speed serial data communication between computers and related devices.Continue Reading
fractional T1
A fractional T1 or T3 line is a T1 or T3 digital phone line in the North American T-carrier system that is leased to a customer at a fraction of its data-carrying capacity and at a correspondingly lower cost.Continue Reading
conductance
Conductance is an expression of the ease with which electric current flows through a substance.Continue Reading
triplecast
A triplecast (TM) is the simultaneous broadcast of a program on television, radio, and an Internet site or channel.Continue Reading
EPOC
EPOC is an operating system designed for small, portable computer-telephones with wireless access to phone and other information services.Continue Reading
brouter
A brouter (pronounced BRAU-tuhr or sometimes BEE-rau-tuhr) is a network bridge and a router combined in a single product.Continue Reading
home network
Using Mobile IP (Mobile Internet Protocol), the home network is where a mobile device has its permanent IP address.Continue Reading
Preboot Execution Environment (PXE)
The Preboot Execution Environment (PXE) is an industry standard client/server interface that allows networked computers that are not yet loaded with an operating system to be configured and booted remotely by an administrator.Continue Reading
repeater
In digital communication systems, a repeater is a device that receives a digital signal on an electromagnetic or optical transmission medium and regenerates the signal along the next leg of the medium.Continue Reading
multihomed
Multihomed describes a computer host that has multiple IP addresses to connected networks.Continue Reading
Point-to-Point Tunneling Protocol (PPTP)
Point-to-Point Tunneling Protocol (PPTP) is a protocol (set of communication rules) that allows corporations to extend their own corporate network through private "tunnels" over the public Internet.Continue Reading
plesiochronous
Plesiochronous (pronounced plee-see-AH-krun-us, from Greek plesos, meaning close, and chronos, meaning time) is an adjective that describes operations that are almost, but not quite, in synchronization - in other words, almost synchronous.Continue Reading
erbium amplifier
An erbium amplifier, also called optical amplifier or an erbium-doped fiber amplifier or EDFA, is an optical or IR repeater that amplifies a modulated laser beam directly, without opto-electronic and electro-optical conversion.Continue Reading
active network
An active network is a network in which the nodes are programmed to perform custom operations on the messages that pass through the node.Continue Reading
B-channel (bearer channel)
In the Integrated Services Digital Network (ISDN), the B-channel is the channel that carries the main data.Continue Reading
ARPA (Advanced Research Projects Agency)
An agency of the United States Department of Defense, ARPA (Advanced Research Projects Agency) underwrote development for the precursor of the Internet, known as ARPANET. Initially a modest network of four interconnected university computers, ...Continue Reading