The symbol designation for electromotive force, or voltage.
E equals electronic, as in e-mail or e-commerce. Typically e means something over the Internet.
Ear & Mouth, Earth and Magneto, rEceive and transMit (take your choice). In telephony, a trunking arrangement that is generally used for two way (either side may initiate actions) switch-to-switch or switch-to-network connections. It also frequently used for computer telephony system to switch connections. See E & M Leads.
The pair of wires carrying signals between trunk equipment and a separate signaling equipment unit. The "M" lead transmits a ground or battery conditions to the signaling equipment. The "E" lead receives open or ground signals from the signaling equipment. These leads are also known as Ear and Mouth Leads. The Ear lead typically means to receive and the Mouth lead typically means to transmit. Changes of voltage on these leads convey such information as seizure of circuit, recognition of seizure, release of circuit, dialed digits, etc. In the old days it was the PBX operators who originated trunk calls by asking the long distance carrier for free trunks using their mouth or M lead. If the carrier had a free trunk, the PBX heard about it through its ear or E lead. See also E & M and E & M SIGNALING.
In telephony, an arrangement that uses separate leads, called respectively the "E" lead and "M" lead, for signaling and supervisory purposes. The near end signals the far end by applying -48 volts dc (vdc) to the "M" lead, which results in a ground being applied to the far end's "E" lead. When -48 vdc is applied to the far end "M" lead, the near-end "E" lead is grounded. The "E" originally stood for "ear," i.e., when the near-end "E" lead was grounded, the far end was calling and "wanted your ear." The "M" originally stood for "mouth," because when the near-end wanted to call (i.e., speak to) the far end, -48 vdc was applied to that lead.
When a PBX wishes to connect to another PBX directly or to a remote PBX or extension telephone over a leased voice grade line, a channel on T-1, the PBX uses a special line interface which is quite different from that which it uses to interface to the phones it's attached directly to (i.e. with in-building wires). The basic reason for the difference between a normal extension interface and the long distance interface is that the signaling requirements differ ” even if the voice signal parameters such as level and two-wire , 4- wire remain the same. When dealing with tie lines or trunks it is costly, inefficient and too slow for a PBX to do what an extension telephone would do, i.e. go off hook, wait for dial tone, dial, wait for ringing to stop, etc. The E&M tie trunk interface device is the closest thing there is to a standard that exists in the PBX, T-1 multiplexer, voice digitizer telco world. But even then it comes in at least five different flavors. E&M signaling is the most common interface signaling method used to interconnect switching signaling systems with transmission signaling systems.
E&M signaling can be either 2-wire or 4-wire. There are mainly 5 types of E&M signaling:
Type 1: 2-wire; E and M leads. Commonly used in North America
Condition M lead E lead
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Ground Open
Off-hook Battery Ground
Type II: 4-wire; E, M, SG, SB leads. Slightly less common than type 1 in North America
Condition M-lead / SB E-lead / SG
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Open Open
Off-hook Battery Ground
Type III: 4-wire; E, M, SG, SB leads. Rarely used in North America
Condition M-lead / SB E-lead / SG
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Ground Open
Off-hook Loop Current Ground
Type IV: 4-wire; E, M, SG, SB leads. Extremely rare in North America
Condition M-lead / SBE-lead / SG
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Open Open
Off-hook Ground Ground
Type V: 2-wire; E and M leads. Commonly used outside of North America
Condition M lead E lead
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Open Open
Off-hook Ground Ground
Type SSDC5: 2-wire; E and M leads. British Telecom Standard. This type is similar to type 1 and V, but not the same.
Condition M lead E lead
” ” ” ” ”- ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ”-
On-hook Earth-Off Earth-Off
Off-hook Earth-On Earth-On
See E & M and E & M Leads.
The optical band, or window, specified by the ITU-T at a wavelength range between 1360nm and 1460nm (nanometers) for fiber optic transmission systems. See also C-Band, L-Band, O-Band, S-Band, and U-Band.
A 10 MHz PCS carrier serving a Basic Trading Area in the frequency block 1885 ” 1890 MHz paired with 1965 ” 1970 MHz.
E stands for echo. It is the 16 Kbps ISDN basic rate channel echoing contents of DCEs to DTEs. Used in bidding for access to multipoint link.
Extended Link. A Signaling System 7 (SS7) connection. This protocol controls all transfers between COs in North America. A SS7 signaling link used to connect a Signaling End Point (SEP) to an STP pair not considered its home STP pair.
A LAN application that fetches messages from one electronic mail system, translates them to the format of another electronic mail system, and then sends them to the "post office" of that other system. The post office is the public entry point ” the place you put mail you want the other system to receive.
A expansion port on a switch. It is used to link multiple switches together into a Fibre Channel fabric. See Fibre Channel.
Electronic purse. An electronic monetary transaction card being proposed by several government agencies.
From Network World, December 15, 1997: "E Rate is the program President Clinton and Vice President Gore are referring to when they say they want every classroom connected to the Internet by the year 2000. It grants elementary and secondary schools a discount on carrier services, including not only Internet access but also a raft of other offerings."
The European equivalent of the North American 1.544 million bits per second (Mbps) T-1,except that E-1 carries information at the rate of 2.048 million bits per second. This is the rate used by European CEPT carriers to transmit 30 64 Kbps digital channels for voice or data calls, plus a 64 kilobits per second (Kbps) channel for signaling, and a 64 Kbps channel for framing (synchronization) and maintenance. CEPT stands for the Conference of European Postal and Telecommunication Administrations. Since robbed-bit signaling is not used (as it is for T-1 in North America) all 8 bits per channel are used to code the wave- shape sample. See E1, E2, E3, and T-1.
Interim data signal that carries four multiplexed E-1 signals. Effective data rate is 8.448 million bits per second (Mbps). See E1, E3 and T-1.
CEPT signal which carries 16 CEPT E-1s and overhead. Effective data rate is 34.368 million bits per second (Mbps).
See the next two definitions.
In the US emergency services telephone network, the E- 911 Control Office is the central office that provides the tandem switching of 911 calls. Each E-911 public safety answering point (PSAP) connects to one or more E-911 Control Offices. The E-911 Control Offices delivers 911 voice calls, with Automatic Number Identification, to the PSAP and provides normal and emergency-specific switching functions. The specialized switch at the E-911 Control Office is known as an E-911 Tandem or Selective Router.
Enhanced 911 service. Dial 911 in most major cities and you'll be connected with an emergency service run typically by a combination of the local police and local fire departments. 911 service becomes enhanced 911 emergency reporting service when there is a minimum of two special features added to it. E-911 provides ANI (Automatic Number Identification) and ALI (Automatic Location Information) to the 911 operator. Picture: A call comes in. Someone is dying. The 911 operator's screen comes alive as his phone rings. The number calling is on the screen. The caller is dying and needs an ambulance. The operator punches a button or two and his screen immediately indicates the location of the ambulance dispatch center nearest the caller. The operator contacts the dispatch center, another button may dispatch a fax of a map of how to get there to the ambulance and an ambulance gets there in short order and saves a life. (Remember, this is a book, not the real world.) See also CESID and PSAP for a full explanation of how the caller's location is sent. See E-911 Control Office.
Extended-Broadcast Control CHannel. A logical channel element of the BCCH signaling and control channel used in digital cellular networks employing TDMA (Time Division Multiple Access), as defined by IS-136. See also BCCH, IS-136 and TDMA.
See E Band.
A smooth change in the direction of the axis of a waveguide , throughout which the axis remains in a plane parallel to the direction of electric E-field (transverse) polarization.
An Ecommerce term for an electronic check. The E-check is a demand for payment which is sent electronically over a network from the buyer to the seller. The e-check subsequently is sent from the seller to the seller's bank, and then to the buyer's bank. See also E-Commerce.
Electronic Commerce. Buying and selling over the public Internet, the public Web and corporate Internets. I prefer ecommerce to e-commerce. But you see it spelled both ways. Predictions for the amount of ecommerce should not be underestimated. See the Internet.
E-DSS1 is the European shorthand way of saying Euro-ISDN,
Enhanced IDE. An enhancement to the original IDE disk drive found on many PCs. E-IDE raises the storage capacity limit from 504 megabytes to 8,033 megabytes and the data transfer rate from up to 3 megabytes per second to up to 16.6 megabytes per second. See also Enhanced IDE.
The network interface between the Cellular Digital Packet Data (CDPD) networks and other external networks.
Electronic Mail. Also spelled email, which is this dictionary's preferred spelling.
Electronic nose, gas chromatograph detection systems. These can detect and analyze target samples for a wide variety of applications as in security control, environmental protection control, food and drug safety control.
Enhanced Observed Time Difference is a new technology that could be used in mobile phones for location based services. The E-OTD positioning method, generally relies upon measuring the time at which signals from the Base Transceiver Station (BTS) arrive at two geographically dispersed locations ” the mobile phone/station (MS) itself and a fixed measuring point known as the Location Measurement Unit (LMU) whose location is known. The position of the MS (also called a cell phone) is determined by comparing the time differences between the two sets of timing measurements. To obtain accurate triangulation, OTD measurements are needed from at least three geographically distinct BTSs. Based on the measured values, the location of the MS can be calculated either in the network or in the MS itself, if all the needed information is available in the MS. The terms "MS-assisted" applies to the former method and "MS-based" to the latter. The MS performs measurements without the need for any additional hardware. To obtain accurate triangulation, OTD measurements are needed from at least three geographically distinct BTSs. Based on the measured values, the location of the MS can be calculated either in the network or in the MS itself, if all the needed information is available in the MS. The terms "MS-assisted" applies to the former method and "MS-based" to the latter. See Location Services.
Electronic Rate. A special discounted rate for Internet access for schools and libraries, e-rate was established as part of the Telecommunications Act of 1996. Technically known as the Schools and Libraries Universal Service Program, e-rate is funded through a portion of the special surcharges of up to five percent on every telephone bill. The carriers remit a portion of those surcharges to the Universal Service Fund, which is administered by the Universal Service Administrative Company (USAC), a not-for-profit corporation established and operated by the National Exchange Carriers Association (NECA). USAC distributes the designated funds to the Schools and Libraries Corporation (SLC) and to the Rural Health Care Corporation (RHCC), which now are divisions of USAC. The SLD (Schools and Libraries Division) get up to $2.25 billion per year, and the RHCD (Rural Health Care Division) up to $400 million per year, with the funds parceled out after the usual ton of paperwork is submitted and dissected. E-rate subsidies are for internal wiring, telecommunications services, and Internet access.
As it sounds, e-signatures are signatures that are recorded and transmitted digitally. They have advantages over actual signatures in that 30 physical aspects of a signature are recorded in an e-signature, making it harder to forge .
Electronic Stamp. Developed by E-Stamp Inc., and planned for trial by the USPS (U.S. Postal Service), the E-Stamp is a means for buying postage over the Internet. In support of a corporate Intranet post office, the system comprises PC software, a small security device which attaches to a user 's printer port, and 1,024-bit encryption software for purposes of security. Think of it as a PC-based postage meter which can be refreshed over the Internet.
A squeezing of electronic and retail. Really awful . I prefer ecommerce. See Ecommerce and E-tailer.
A company that does most of its retailing , consumer-to-consumer business over the Internet. Such companies include priceline.com, ftd.com, 1-800-flowers.com, ebay and expedia.com.
Extended Time Division Multiple Access. A proposed, new, standard for cellular. Other standards are TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access) and NAMPS (Narrow Advanced Mobile Phone Service). Refers to the extended (digital cellular) transmission technology developed by Hughes Network Systems. E-TDMA is alleged to have 15 times the capacity of today's analog cellular phone systems ” in other words to allow the simultaneous use of 15 times as many cellular phones as today's analog cellular phone system.
E-wear is a line of wearable portable audio products from Panasonic.
Magazines that are published (i.e. made public) on the World Wide Web. Typically an e-zine is available for anyone to read who wants to visit the site the electronic magazine is located at. An e-zine is also called a Webzine.
The ITU-T recommendation for GSTN (Global Switched Telephone Network) numbering, E.164 is a 16-digit numbering scheme that provides a unique telephone number for every subscriber in the world. See also ENUM.
The ITU-T recommendation for international toll-free numbers, known as Universal International Freephone Numbers (UIFNs). Such numbers remain the same throughout the world, regardless of country or telecommunications carrier. "Freephone" is a service that permits the cost of a telephone call to be charged to the called party, rather than the calling party. In North America, "freephone" numbers are known as "toll-free" or IN-WATS, and include the 800, 888, 877 and 866 area codes. See also IN-WATS and UIFN.
Energy (E) equals Mass (M) times the Velocity of Light (C) squared (^2, as in superscript 2). E equals MC squared is Albert Einstein's famous equation which shows the relationship of mass to energy. One gram of mass ” half the weight of a Lifesaver candy - was converted into energy over Hiroshima in 1945.
Name given to the CEPT (Conference of European Postal and Telecommunication Administration) digital telephony format devised by the ITU-T that carries data at the rate of 2.048 million bits per second (DS-1 level). It's designed to carry 32 (thirty two) 64 Kbps digital channels. E1 is the rate used by European CEPT carriers to transmit thirty 64 Kbps digital channels for voice or data calls, plus a 64 Kbps channel for signaling, and a 64 Kbps channel for framing and maintenance. Plesiochronous means "almost synchronous." In the network sense, when two networks operate with clocks of sufficiently high quality such that the signals in the two networks are nearly synchronous, the networks are plesiochronous. In the synchronization hierarchy, stratum I clocks are required for plesiochronous operation. My personal preference is to use E-1 instead of E1, but it's written both ways. See E-1 and T-1, which is the North American equivalent.
Emergency call number in Europe. The European equivalent of E911. E stands for electronic.
The domain established by the IAB (Internet Architecture Board) for ENUM. See also E.164 and ENUM.
Data signal that carries four multiplexed E-1 signals. Effective data rate is 8.448 million bits per second or 128 simultaneous conversations.
Signal which carries 16 CEPT E-1 circuits and overhead. Effective data rate is 34.368 million bits per second or 512 simultaneous voice conversations. Also known as CEPT3.
Signal which carries four E3 channels ” or 139.264 million bits per second, or 1,920 simultaneous voice conversations.
Signal which carries four E4 channels ” or 565.148 million bits per second, or 7,680 simultaneous voice conversations.
See Enhanced 911.
See Equal Access and Address Field Extension.
The European Association of Consumer Electronics Manufacturers.
Engineering and Administrative Data Acquisition System.
EADAS NetWork Management.
Enterprise Application Integration. See also EPO.
European Article Numbering. EAN is the universal bar coding system for product identification at point of sale, now adopted almost worldwide. There are variants, e.g. in Japan in the term is EAN/J.
Extensible Authentication Protocol, as defined in IETF RFC 2284, is an authentication protocol that runs over Layer 2, the Data Link Layer (DLL), of the OSI Reference Model. As EAP does not require IP (Internet Protocol), it includes its own support for message delivery and retransmission. EAP was developed for use over PPP (Point-to-Point Protocol), although it now is in use in IEEE 802 LAN environments, including 802.3 Ethernet LANs, 802.5 Token Ring LANs, and 802.11 Ethernet WLANs (Wireless LANs), and is specified in 802.1X. In such a LAN environment, EAP takes the form of EAPOL (EAP Over LAN). EAP supports multiple authentication mechanisms. See also 802.1X, 802.3, 802.5, Authentication, IP, LAN, OSI Reference Model, PPP, and WLAN.
See E & M Signaling.
An sound version of the icon, a short burst of sound that is musical but not music. Earcons will be used by telephone companies and wireless providers as tiny branding signatures. Cynthia Sikora and Linda Roberts of Bell Labs are working on earcons. In a research paper they talk about "steer(ing) the emotional reaction of the listener in support of the desired image." Expect to be inundated by a symphony of earcons, emanating from phones, Internet enabled PDAs, wearable electronics, computers, refrigerators, medicine chests, says Faith Popcorn's "Dictionary of the Future."
When he was young and immature, Dan Good was an early adopter. That meant he would beg, borrow and steal to get the beta release of the first release of any software that would, allegedly, improve his life, his productivity, his well- bearing or his stature among his friends . Now he's older and wiser, he knows "early adopter" software is riddled with bugs. Dan now knows not to waste the time removing the buggy software and going back to his original software. He knows it is better to stick with tried and true software ” preferably software that has enjoyed at least one "service release" ” a fancy Microsoft word for code that fixes the bugs in the original piece of software.
This is a method of token passing which allows for two tokens to exist on the network simultaneously . It is used primarily in 16 million bit per second (Mbps) token ring LANs. On a regular four million bit per second token ring LAN, the token is passed on only after the sending computer receives its message back from the destination computer. With early token release, the sending computer does not wait for its message to return before passing the token. This means there are two tokens on the network at the same time. This is done to take advantage of the idle time created on the faster token ring. While the message is moving to its destination and back the sending computer is idle. On the four Mbps token ring, this is not much of a problem since most of the time the message is on the ring. On the 16 Mbps token ring less of this idle time is transmission time and more is taken by copying the message to the token ring card. That is, on the faster ring, there is more of a window for a second token. Early token release is especially helpful when traffic is heavy.
European Academic Research Network. A network using BITNET technology connecting universities and research labs in Europe.
The company whose network carried an LD call and who is entitled to the revenue associated with the call. This may or may not be the same as the Billing Company.
The month service or equipment was delivered to a customer. In usage, this is the month the phone call took place. For nonrecurring charges (NRCs), it is the month the service or equipment was delivered.
Calculated by dividing a company's total after-tax profits by the company's number of common shares outstanding. Earnings per share can be used as an indicator of growth and profitability.
An acronym for Electrically Alterable Read-Only Memory. A type of ROM chip which can be erased and reprogrammed without having to be removed from the circuit board. An EAROM is reprogrammed electrically faster and more conveniently than an EPROM (Erasable Programmable Read-Only Memory). An EAROM chip does not lose its memory when power is turned off.
The term the English use for what Americans call ground. See Grounding .
The connection of an electrical system to earth. This connection is necessary to provide lightning and static protection as well as to establish the zero-voltage reference for the system. See Earth Grounding.
The conductor which connects directly to earth ground usually via a water pipe or possibly via a copper rod driven into the earth. This ground is different than the logic ground used in electronic circuits.
The conducting body in contact with the earth. The grounding electrode may be a metallic cold water pipe when used in conjunction with a driven rod, a mat, a grid, etc. Earth should never be used as the sole equipment grounding conductor.
The purpose of earth grounding is essentially threefold:
Static protection; and
Establish a zero voltage reference. See Ground and Grounding.
A ground-based antenna and associated equipment used to receive and/or transmit telecommunications signals via satellite. Earth stations come in all sizes, shapes and purposes. For example,M most earth stations used by cable television operators are receive-only. Other terms used synonymously with "earth station" include downlink, ground station, and TVRO ("Television Receive Only").
Microwave radio equipment used to communicate with communications satellites . This term is most commonly associated with VSAT's, TVRO's, portable and mobile satellite operations, particularly domestic.
There are two distinct and unique categories in the broad area called grounding. One is earthing, which is designed to guard against the adverse effects of lightning, assist in the reduction of static and bring a zero-voltage reference to system components in order that logic circuits can communicate from a known reference. The other category of grounding is known as equipment grounding. This is the primary means of protecting personnel from electrocution. According to the Electric Power Research Institute, "electrical wiring and grounding defects are the source of 90% of all equipment failures." Many telephone system installer/contractors have found that checking for and repairing grounding problems can solve many telephone system problems, especially intermittent "no trouble found" problems. As electrical connections age, they loosen, corrode and become subject to thermal stress that can increase the impedance of the ground path or increase the resistance of the connection to earth. Equipment is available to test for proper grounding. One of our favorite devices is made by Ecos Electronics in Oak Park, IL. Before you attach any equipment (computer, telephone, hi-fi set, etc.) to an improperly grounded electrical outlet, you should have the problems corrected. See also Ground and Grounding.
Emergency Alert System. A system for radio and TV that is designed to provide warnings in the event of emergencies. The system was originally designed during the Cold War to provide the President with a means to address the American people in the event of a national emergency. It has never been used for that purpose (thank God), but it has been used to warn of natural disasters. The current use of the Emergency Alert System is voluntary and involves participation by three groups ”
Radio, TV and cable broadcasters,
The National Weather Service and
State and local emergency management agencies. The FCC reports that 85% of the messages have dealt with weather emergencies.
Extended Area Service. A novel name for a larger than normal local telephone calling area. The local phone company extends its subscribers the option of paying less per month for a small calling area and paying extra per individual call outside that area (i.e. the extended area), or paying more per month flat rate but having a larger calling area (i.e. having extended area service).
Electronic Article Surveillance. See also RFID.
A voice processing applications generator from Expert Systems, Inc. in Atlanta, GA.
An Easter Egg, in computer parlance, is a tiny credits screen or secret surprise (e.g., graphic or sound effect) hidden by a programmer in the program code. An Easter Egg is designed to appear only when you perform some incredibly improbable sequence of keystrokes and mouse clicks, commonly if you're another programmer disassembling or browsing the source code. Easter Eggs are intended to be amusing, rather than destructive, although they do result in code bloat (i.e., eat up memory and other resources). Easter Eggs are also used for checking software theft. By hitting the secret keystrokes, you can tell if the code was stolen. Easter Eggs are hidden in all sorts of programs, including Lotus Notes and Microsoft Excel and Word. See also Code Bloat.
A triangular antenna mounting system used for attaching a mast to the eave or gable of a peaked roof.
Electronic Automatic eXchange. Term used throughout the non-Bell telephone industry to refer to an electronic central office. Similar to ESS (Electronic Switching System), the term used by AT&T and the Bell operating telephone companies.
Exabyte. See Exabyte.
(Pronounced Eb-si-dic.) Extended Binary Coded Decimal Interchange Code. It is the way IBM codes characters , letters and numbers into a digital binary stream for use in its larger computers. EBCDIC codes characters into eight bits. This gives it 256 possible characters, 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256. See also Extended Character Set. EBCDIC is mainly used in IBM mainframes and minicomputers, while ASCII is used in IBM and non- IBM desktop microcomputers. EBCDIC is not compatible with ASCII, meaning that a computer which understands EBCDIC will not understand ASCII. But there are many real-time and non-real time translation programs that will convert text files back and forth. See ASCII.
Effective Bill Date. This date is used when the effective date for billing differs from the completion date. In the bill section of an order, EBD applies to the total order.
Electronic Business Data Interchange. Term for EDI (Electronic Data Interchange). See EDI.
Earnings Before Interest, Taxes, Depreciation and Amortization. All financial accounting can mislead or enlighten. I've never been a big fan of EBIDTA. Moody's Investors Service says it's more often used as an accounting gimmick to dress up a company's financial picture to make it look rosier than it really is and deflect investor attention away from bad news. But here's the way it was explained to me: EBIDTA is a way of looking at the earnings of a firm. By ignoring taxes, depreciation and amortization, EBITDA attempts to establish a "common ground" by which the profitability of different firms can be measured, given the likelihood that the ownership of these firms may shortly change and the new owner will have his own taxes (perhaps lower), may renegotiate the company's loans (perhaps cheaper) and may change the company's depreciation and amortization. I hear the word EBITDA more in acquisition scenarios than in ongoing companies that are not going to be acquired . EBITDA has also been used in the valuation of companies which are losing money, such as several wireless or long distance carrier telecom companies. The major factor in their losing money is often the high interest on their heavy borrowings which they used to finance their networks. Removing that interest (as in EBITDA) makes them wonderful as they're now earning money. I believe these companies should be measured on their earnings after interest, taxes and depreciation - that's commonly called net income ” since that provides a better measure of the efficiency of their business, including their borrowings which are integral to their business.
European Backbone. A pan-European network backbone service.
Electronic Bill Presentation and Payment.
Billing and payment over the Internet. Developing standards include Open Financial Exchange (OFX) and GOLD. See also Electronic Commerce, GOLD and OFX.
Electronic Business Set.
Enhanced Business Service (also known as P-Phone) is an analog Centrex offering provided by Nortel Networks. It operates over a single-pair subscriber loop., providing normal full duplex audio conversations and a secondary 8 KHz half-duplex amplitude shift- keyed signal, which is used to transmit signaling information to and from the Nortel Networks-equipped central office.
Emergency Broadcast System. Some local radio stations have volunteered their services to be part of a group of radio stations which would broadcast information should there be a public emergency. They operate the EBS under the aegis of the Federal Communications Commission. Such emergency would be a natural disaster, a technological disaster or a war. In 1994, Emergency Broadcast System changed. For a full explanation, see Emergency Broadcast System.
End System Bye packet. Part of CDPD Mobile End System (M-ES) registration procedures.
European Broadcasting Union. Formed in 1950 and headquartered in Geneva, Switzerland, the EBU was formed to address technical and legal problems in Western European broadcasting. The EBU now includes former Soviet Bloc broadcasters, having merged with the former International Radio and Television Organization (OIRT) in 1993. Associate membership includes 30 countries in Africa, the Americas, and Asia. The EBU runs EUROVISION, a permanent network of 13 channels on a Eutelsat satellite, plus 5,500 kilometers of permanently leased terrestrial circuits; the network serves as a vehicle for daily news and program exchanges. www.ebu.ch.
European Community, or European Economic Community (EEC). Now called the European Union. Also known as the Common Market; an organization of 15 nations in Western Europe that has its own institutional structure and decision-making framework. It was formed on November 1, 1993. The intent of the organization is to promote trade and reduce barriers. Member nations are Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, Sweden and the United Kingdom of Great Britain and Northern Ireland
Electrical Carrier. OC means optical carrier.
electrical carrier Level 1: 51.84 Mb/s. This is an STS-1 signal conditioned for transmission over a relatively short span of coax, usually between collocated network elements.
Exchange Carrier Association. An organization set up under the FCC's order on access charges to perform numerous planning and management functions required to implement and operate the industrywide access charge system.
Developed by DigiCash and the Mark Twain Bank, ecash is the ability to use real money in a electronic purchasing system over the World Wide Web. The process involves you sending a check to Mark Twain Bank which in turn sends you software which gives you access to the Ecash Mint where you draw funds to your hard drive for use when purchasing goods and services on the Internet. www.marktwain.com.
Exchange Carrier Code. Four letter numeric originally assigned by Bellcore (now called Telcordia Technologies) to identify CLECs ” competitive local exchange carriers, i.e. local telephone companies. This code is used solely by Bell legacy computer systems. Most competitive telecom companies find this code repetitive because there is already an ACNA code and an OCN (Operating Company Number) code that identifies carriers. However, the Bell Companies do not want to do away with this code because there is a field in their system for it. Some telephone companies (such as Southwestern Bell) call the ECC number an AECN, which stands for an Alternate Exchange Carrier Name. See also AECN.
Elliptic Curve Cryptography. The Wireless Application Protocol (WAP) Forum has added ECC into Version 1.0 of its specification for wireless security that is bandwidth, memory and power efficient. More details www.certicom.com.
Electronic Common Control. The generic term that applies to the third generation of automatic voice circuit switches, such as PBXs, COs (Central Offices), and toll tandems. ECC switches essentially are highly specialized computer systems with a common set of programmed logic that controls the setup, maintenance and teardown of port-to-port connections through a switching matrix comprising multiple centralized buses. A set of common logic also supports a wide array of features. ECC switches rendered obsolete electromagnetic Xbar (crossbar), which earlier rendered obsolete electromechanical SxS (Step-by- Step) systems, which had rendered obsolete manual cordboards. See also Cord Board, SxS, and Xbar.
Error-correcting code memory, often used in local area network servers. ECC memory tests for and corrects errors on the fly, using circuitry that generates checksums to correct errors greater than one hit.
Non-circular; elliptical (applied to an orbit ).
Like concentricity a measure of the center of a conductor's location with respect to the circular cross section of the insulation. Expressed as a percentage of center displacement of one circle within the other.
In orbit geometry, the deviation of the center of an orbit from the center of the earth. The theoretically perfect geostationary satellite orbit has zero eccentricity.
Odd or whimsical behavior. In other words, behavior which deviates from and established pattern, rule, or norm. The term comes from "eccentric," which applies to rich people. Poor people who exhibit eccentric behavior are just "crazy." Rich people who are eccentric are successful. In short, there is no valid definition.
Exchange Company Circuit. A circuit ID for a trunk line. Such term is often used between telephone companies to identify lines that one is leasing to the other. See also FOC.
Enhanced Call Handling. ECH systems are those in which a telephone call is handled "intelligently" b a variety of network, human, computer and telecommunications resources. ECH systems cover those from voice mail, to interactive voice response to computer telephone integration to fax-on-demand to complex telephone networks.
The name of a startup company in Palo Alto that is making a microprocessor chip destined for mundane household appliances like toasters, air conditioners, ovens, etc. The idea is that chip will be used by these devices to talk to other devices and thus coordinate their coming on and going off and doing things. The chips are destined to be networked together. Early uses for the chip includes smoke detectors which call you when they detect smoke and wall switches that detect when you come into a room and turn the lights on.
The code name for an alleged automated global interception and relay system operated by the NSA (National Security Agency) and intelligence agencies in four other countries, including Australia, Britain and Germany. "Alleged" as the NSA refuses to either confirm or deny its existence. Echelon allegedly comprises a networked supercomputer that monitors all international voice, e-mail and fax traffic, and other electronic data transfers, including wireless communications such as cellular and pager transmissions. The Echelon supercomputers reportedly analyze as many as two million transmission per day, looking for key words such as "bomb," " assassin ," "militia," "gun," "explosives," "Delta Force," "Branch Davidian," and "cocaine" and all manner of drug- related jargon. If such a key word is detected during one of your transmissions, the transmission is recorded and analyzed . What happens from that point forward has yet to be reported . Echelon allegedly comprises five spy satellites, numerous terrestrial radio antennas, Internet packet sniffers, Web search engines, and surveillance devices placed on submarine cables by divers.
European Commission Host Organization.
The echo heard by a listener when holding a seashell to the ear does not come from the shell itself. It is the echo of the blood pulsing in the listener's ear.
Echo is exactly what you expect it to mean. You hear yourself speak. Echoes happen in both voice and data conversation. Echoes are good and bad. In voice, an echo happens when the equipment meant to amplify the voice of the party at one end, picks up the signals from the party at the other end, and amplifies them back to that party. Some echo is acceptable (in fact, almost a necessity) in voice conversations. It's called SIDETONE. When the speaker can hear himself speak through the receiver, sidetone gives the speaker some feeling his conversation is actually going through. But too much (i.e. too loud) echo is unacceptable. There are devices called echo suppressors, which do exactly that.
In low speed or on-line data conversations, an echo is positively vital . An echo in a data conversation is where I send my words to the distant computer which "echoes" them back to me and my screen displays them. This way I can visually check if the distant computer received my words/data accurately. In some software programs there's a command called ECHO or ECHOPLEX. Switch it one way, the distant computer echoes the words to my screen. Switch it the other, the words I'm typing on my keyboard are put on my screen.
There are two basic transmission modes in data communications ” full duplex and half duplex. In full duplex, I have simultaneous two-way data flowing . In full duplex, I therefore have the capacity to "echo" back the data I am sending and have it displayed on my screen. But this "echoing" depends on the capability and/or programming of the computer at the other end. All dial-up services ” Tymnet, GTE Telenet, MCI Mail, etc. ” will echo my data back to me so I can check it.
Some computers, such as the extremely dumb Compugraphic typesetter which typeset the first edition of this book, won't send an echo. In this case, if I want to see the data I am sending, I can change the parameters on my communications software to "half duplex." This way I will see what I am sending, but I will not see what the computer is receiving. Which may be very different. (And with our Compugraphic often is.) Of course, watching characters being echoed across your screen is a very poor method of data transmission and only useful in on-line transmissions. Some form of error-checking protocol is much better.
An echo is also a public discussion group that extends over more than one BBS (bulletin board system) via echomail.
In a communications circuit (4- or 2-wire) in which the two directions of transmission can be separated from each other, the attenuation of echo signals that return to the input of the circuit under consideration. Echo attenuation is expressed as the ratio of the transmitted power to the received echo power in decibels. See also Attenuation.
Technique that allows for the isolation and filtering of unwanted signals caused by echoes from the main transmitted signal. An echo cancellation device puts a signal on the return transmission path which is equal and opposite to the echo signal. Echo cancellation allows full duplex modems to send and receive on the same frequency. Network-based echo cancellation can interfere with modems which perform their own echo cancellation. To avoid cancellation problems, modems capable of echo cancellation (such as V.32 modems) send a unique answer tone with a phase reversal every half second. The network echo cancellers detect the phase reversal in the answer tone and disable themselves . Contrast with echo suppression. See echo canceller.
Device that allows for the isolation and filtering of unwanted signal caused by echoes from the main transmitted signal. In data communications networks, echo cancelers are used in the same way as PADS are in the network, but some brands of echo cancelers have the ability of being disabled by a 2100 Hertz tone transmitted by the data device prior to the exchange of the data device's handshaking protocol. If the echo canceler cannot be disabled by the data device, it will block the data call from completing. See also echo cancellation.
A technique for verifying data sent to another location by returning the received data (echoing it back) to the sending end.
A mathematical process where an echo is conceptually created from an audio waveform and subtracted from that form. The process involves sampling the acoustical properties of a room and guessing what form an echo might take, then removing that information from the audio signal.
ERL. The difference between a frequency signal and the echo on that signal as it reaches its destination. For example, a way of measuring echo return loss is to say it's the frequency-weighted measure of return loss over the middle of the voiceband (approx. 560-1965 Hz) where talker echo is most annoying.
The process of turning off reverse transmissions on a telephone line to reduce the annoying effects of echoes in telephone connections, especially on satellite circuits. An active echo suppressor impedes full-duplex data transmission. Contrast with echo cancellation.
Used to reduce the annoying effects of echoes in telephone connections. The worst echoes occur on satellite circuits. An echo suppressor works by turning off transmission in the reverse direction while a person is talking, thus effectively making the circuit one way. An echo suppressor obviously impedes full-duplex data ” data flowing both ways simultaneously. Echo suppressors are turned off by the high-pitched tone (typically 2025 Hz) in the answering modem, which it uses to signal it's answered the phone and is ready for a data conversation.
An echo suppressor disabler is a device which causes an echo suppressor to be disabled (i.e. turned off). Echo suppressors are turned off by the high-pitched tone (typically 2025 Hz) in the answering modem, which it uses to signal it's answered the phone and is ready for a data conversation. A disabled echo suppressor stays disabled until the circuit is disconnected and restored to its "ready" connection. Because an echo suppressor hinders full duplex transmission in data communications, it is necessary to disable the echo suppressor.
A public message area or conference on a bulletin board system (BBS) that is "echoed" to other systems in a BBS network. EchoMail is organized into different groups, each with a different topic and the term normally references communications on a FidoNet network. Also a term referring to the electronic transfer of messages between bulletin board systems.
A way of checking the accuracy of data transmitted whereby the data received are returned to the sender for comparison with the original data. Somewhat time consuming. Used typically in slow speed transmissions. See Echo.
European Committee for Information Technology testing and Certification.
Emitter Coupled Logic.
Error Correction Mode. An enhancement to Group 3 fax machines. Encapsulated data within HDLC frames providing the received with an opportunity to check for, and request retransmission of garbled data. See Facsimile and V.17.
Originally the European Computer Manufacturers Association, the name was changed to ECMA in 1994. It is an international, Europe-based industry association founded in 1961 and dedicated to the standardization of information and communications systems. ECMA addresses standards in areas such as software engineering and interfaces, APIs and languages, data presentation, character sets and coding schemes, file structures, LAN protocols, IT security, and optical disks. www.ecma.ch. See also CEPT.
Enhanced Cellular Messaging Encryption Algorithm. The Telecommunications Industry Association's CMEA is used for confidentiality of the control channel in the most recent American digital telephony systems. It is a variable-length block cipher. A paper called "Cryptanalysis of the Cellular Message Encryption Algorithm" by Wagner, Schieier, and Kelsey) describes an attack on CMEA that " demonstrates that CMEA is deeply flawed." ECMEA (Enhanced CMEA) corrects the flaw.
Electronic Commerce Modeling Language. This is an Internet commerce tool. Customers are frequently required to enter substantial amounts of information at an Internet merchant site in order to complete a purchase or other transaction, especially the first time they go there. A standard set of information fields is defined as the first version of an Electronic Commerce Modeling Language (ECML) so that this task can be more easily automated, for example by wallet software that could fill in fields. Even for the manual data entry case, customers will be less confused by varying merchant sites if a substantial number adopt these standard fields. In addition, some fields are defined for merchant to consumer communication. See also www.ietf.org/rfc/rfc3106.txt.
Equal Cost Multipath Routing. ECMP distributes traffic across multiple high-band- width links to increase performance. Extreme's OSPF implementation supports multiple equal-cost paths between points and divides traffic evenly among the available paths. As many as four links may be involved in an ECMP link and traffic is shared on an IP source/destination address session basis.
Electronic Communications Network. A term that is applied to those communications networks set up for trading stocks and bonds using PCs and the Internet, or a dial-in circuit into a private network. ECNs are hot and are stealing trading in many of the hottest stocks from New York Stock Exchange and Nasdaq.
European Conference on Optical Communication.
An AT&T term for the maximum bandwidth that a physical medium can support without a significant increase in its cost.
ECCS. The load that should be carried on the last trunk of a high usage trunk group to minimize the total cost of routing the offered traffic, assuming that overflow from the high usage route is offered to an alternate route engineered to meet an objective blocking probability.
The standing joke is that an economist is someone who didn't have the personality to become an accountant. There is also a theory floating around in some academic circles that God invented economists to make weather forecasters and astrologers look good. Economists are incredibly good, I'm told, at predicting the past. Several people have also said, ""If you laid every economist end to end, it would not be a bad thing." For those of you who don't know (or care), my first degree was in Economics. See Accountant .