The Cable Center

This glossary of cable and telecommunications terms is intended to enhance your understanding of this dynamic industry. We are able to present this information with the generous help of CableLabs - consult their website for the most up-to-date information about cable technology.

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Earth Station
Structure, referred to as a “dish,” used for receiving and/ or transmitting those electromagnetic signals coming from or going to a satellite.

Easement
The right to use land for a specific purpose, such as laying cable.

EBITDA
Earnings before interest, taxes, depreciation and amortization. Also known as operating cash flow by many cable television operators. A financial and liquidity measure (proxy for cash flow) for companies with significant fixed investment or acquisition expenses that do not generally report positive net earnings.

EBITA
Earnings before interest, taxes and amortization. Similar to EBITDA, but is reduced to give effect to periodic depreciation expenses.

Echo
A wave which has been reflected at one or more points in the transmission medium, with sufficient magnitude and time difference to be perceived in some manner as a wave distinct from that of the main or primary transmission. Echoes may be either leading or lagging the primary wave and appear on the picture monitor as reflections or “ghosts.” Also known as reflections.

Education Channel
FCC rules require cable systems in the top 100 markets to set aside one channel for educational uses, to be available without cost for the “developmental period.” The developmental period of a cable television system runs for five years from the time that subscriber service began, or five years after the completion of the basic trunk line.

Educational Television Station (ETV)
A non-commercial television station primarily devoted to educational broadcasting.

Electro-Magnetic Interference
Electro-magnetic (EM) interference is caused when magnetic force lines generated by radio waves, electrical current in other phone lines, and events in outer space, like sun-spots, intersect with a telephone wire, generating a slight variation in the electrical current that we hear as “static.” Magnetic interference is the major obstacle to higher modem speeds because they change the very precisely modulated analog signal modems use to transmit and receive data. Today’s 28.8 Kbps “V.34” modems, for example, usually have to “fall back” to lower speeds of 21.6 to 24 Kbps due to EM interference.

Electromagnetic Spectrum
A continuous range of frequencies of electromagnetic radiation (i.e., oscillating electrical and magnetic energy which can travel through space). Within the spectrum, waves have some specified common characteristics; the TV broadcast spectrum, for instance, ranges from 45 to 890 MHz. See Frequency.

Electronic Commerce (E-Commerce)
Used to describe commerce that occurs electronically over the Internet.

Electronic Industries Association (EIA)
A voluntary body of manufacturers which, among other activities, prepares and publishes standards.

Electronic Industry Alliance (EIA)
An industry association accredited by ANSI (American National Standards Institute) to develop standards in the areas of electronic components, consumer electronics, electronic information and telecommunications.

Electronic Key Telephone Service (EKTS)
EKTS features allow a single ISDN SPID or B channel to support multiple directory numbers.

Electronic Program Guide (EPG)
An electronic program guide is an application that displays television program information, including program name, start time, and duration.

Element Management System (EMS)
That contains software applications used for configuration, performance, and faults from one or more network elements. The EMS is a second layer of management in the telecommunications management network (TMN) hierarchy.

Elementary Stream (ES)
An elementary stream is a generic term for one of the coded video, coded audio, or other coded bit streams. One elementary stream is carried in a sequence of PES packets with one and only one stream id.

Emergency Alert System (EAS)
The US federal system for alerting the public to emergencies. EAS is a digital upgrade to the old Emergency Broadcasting System.

Email
The electronic exchange of messages and files between computers on a network, email is the abbreviated form of electronic mail. An e-mail client is usually integrated with popular browsers.

Embedded-Client
A synonym for, and equivalent with, “Embedded Subscriber Media Gateway.”

Embedded Subscriber Media Gateway (E-SMG)
A subscriber media gateway (SMG) with the distinct property that the physical node within the SMG also contains a direct media access control (MAC) layer interface to a DOCSIS access network. The only significant functional difference between an E-SMG and a SMG is that the media signaling and streaming function MAY be capable of directly accessing MAC layer services (traffic management, polling-heartbeats, and authentication functions).

EN
European Norms. Prefix for certain ETSI documents.

Encipherment
A method used to translate plaintext into ciphertext.

Encryption
A form of encoding transmitted data for security purposes. It normally requires the decryption “key” to decipher the transmission upon receipt. The level of security is dependent on the complexity of the key used. A method used to translate plaintext into ciphertext.

Encryption Key
The key used in a cryptographic algorithm to translate the plaintext to ciphertext.

End User
A human being, organization or telecommunications system that accesses the network in order to communicate via the services provided by the network. Also known as customer.

Endpoint
A Terminal, Gateway or Multipoint Conference Unit.

Engineering Change Notice (ECN)
The final step in the procedure to change specifications. An ECN is officially considered to be part of the specification that it modifies.

Engineering Change Order (ECO)
The second step in the procedure to change specifications. CableLabs posts ECOs to Web site EC table and ECO page (with indication of ECO Comment Deadline). CableLabs issues ECO announcement to an Announcement mail list and working group mail lists (with indication of ECO Comment Deadline). DOCSIS, CableHome, OpenCable and PacketCable all utilize a similar process.

Engineering Change Request (ECR)
The first step in the procedure to change specifications. CableLabs issues ECR number, posts to Web site EC table and ECR page. CableLabs sends ECR to subject area working group mail list (and author). DOCSIS, CableHome, OpenCable and PacketCable all utilize a similar process.

Equal Access
The offering of access to local exchange facilities on a non-discriminatory basis.

Equalization
A means of modifying the frequency and/or phase response of an amplifier or network, thereby resulting in a flat overall response.

Equalized Loss
Any loss in cable television systems caused by coaxial cable; also, insertion loss of components designed to match cable loss characteristics.

Equalizing Pulses
Pulses of one half the width of the horizontal sync pulses which are transmitted at twice the rate of the horizontal sync pulses during the blanking intervals immediately preceding and following the vertical sync pulses. The action of these pulses causes the vertical deflection to start at the same time in each interval, and also serves to keep the horizontal sweep circuits in step during the vertical blanking intervals immediately preceding and following the vertical sync pulse.

Error Rate
A measure of the performance of a digital transmission system. It can be specified as a bit error rate (the probability of error per bit transmitted), as a block error rate (the probability of one or more errors in a specified-length block of bits), or in other forms such as percent error-free seconds.

Errored Second
Any 1-sec interval containing at least one bit error.

Ethernet
The most popular LAN technology in use today. The IEEE standard 802.3 defines the rules for configuring an Ethernet network. It is a 10Mbps, 100Mbps, or 1000 Mbps CSMA/CD baseband network that runs over thin coax, thick coax, twisted pair or fiber optic cable.

ETS
European Telecommunications Standard. Prefix for certain ETSI documents.

European Telecommunications Standards Institute (ETSI)
The European equivalent of ANSI (American National Standards Institute).

Event Message
A message capturing a single portion of a connection.

Events
Events are asynchronous communication between applications and the OpenCable system on which they are being executed. They provide communication between solution elements. An event may also refer to a unit of programming, such as a movie, an episode of a television show, a newscast or a sports game.

Exclusivity
The provision in a commercial television film contract that grants exclusive playback rights for the film or episode to a broadcast station in the market it serves. Under the FCC’s rules cable operators cannot carry distant signals which violate local television stations’ exclusivity agreements.

Execution Engine (EE)
The portion of OCAP which will provide a full programming environment for performing complex logic and arithmetic operations which the Presentation Engine (PE) cannot handle alone. In the EE, which will include Sun’s JavaTV programming environment, ITV developers will write interactive applications, in Java, following the OCAP specification. When a cable customer with an OpenCable-compliant set-top box accesses the application through the user interface, the application is transparently downloaded into the box. A Java engine or JAVA Virtual Machine (JVM) resident in the set-top decodes the application downloaded over the network, and runs it. Or the execution engine is a platform-independent interface that permits programmatic content as part of the OpenCable Application Platform.

Extended Subsplit
A frequency division scheme that allows bi-directional traffic on a single coaxial cable. Reverse path signals come to the headend from 5 to 42 MHz. Forward path signals go from the headend from 50 or 54 MHz to the upper frequency limit.

Extensible Hypertext Mark-up Language (XHTML)
A reformulation of HTML in XML.