A place that varies widely depending on where one stands (literally and figuratively), but generally recognized as being located after the point of signal collection, and before the eyeball. At the edge, one thing hands off to another thing — like an optical signal to a radio frequency, or an outside broadband network to an inside broadband network, or something wired to something wireless.

If you’re a network architect, the “edge” of a cable network is generally the place where optics hand off to RF, such as at a distribution hub. Translation: About a mile north of the “last mile.” The devices therein are thus called “edge devices.” Maybe you’ve heard of an “edge QAM,” for instance, which is the spot in a cable broadband network where IP traffic, running over gigabit Ethernet, transfers onto the traditional RF network toward homes.

If you’re a set-top aficionado, the “edge” is the output of that box.

Usage: In general, technological innovation moves the “edge” of the network closer to customers over time.

The raw throughput of a data stream, after subtracting bits associated with overhead information. Overhead, in data parlance, means any bits reserved for identification, error correction, or other chores not directly related to the transmitted payload. The age-old postal system example works here. You write a letter. You put it in an envelope and take it to the post office. The envelope, sender address, return address, and postmark are the overhead. The letter itself is the effective bit rate — the payload.

Usage: After overhead, the effective bit rate of 256 QAM is 38 Mbps.

Software designed to be small and sleek, so that it can be nestled in a consumer electronics or telecommunications device without straining microprocessor or memory resources. Embedded systems are included in fax machines, cell phones, and some set tops. Cable modems are becoming embedded devices, showing up in VoIP adaptors, and, soon enough, consumer electronics devices.

Usage: Ever heard the term e-DOCSIS? That “e” stands for embedded.

In data communications, a method for securing a data stream by encrypting everything except the source (who’s sending) and destination (who’s receiving).

Common in virtual private networks, or VPNs, encapsulation is used to securely connect to a corporate server from a remote location. Encapsulation is a cousin to “tunneling,” where an Internet service provider creates a private path from where you are, to where its servers are, shading everything but the source and destination ID of the packets you’re sending.

Usage: Encapsulation is like sending a letter, instead of a postcard. With a postcard, anyone can see the return address, destination address, and message. A letter is more private, because the envelope protects its contents.

A process for securing data by imprinting it with secret codes. The digital equivalent of scrambling. There are multiple flavors of encryption, which vary by encryption strength. Proprietary cable industry examples include Motorolas DigiCipher and Scientific-Atlantas PowerKEY. Other, more generic versions, decidedly industrial-grade, include triple-DES and AES.

A protocol, developed by the Internet Engineering Task Force’s (IETF’s) Telephone Number Mapping working group, that maps phone numbers to Internet addresses tied to devices like VoIP telephone handsets.

ENUM is one reason you can dial a phone number from a traditional, twisted-pair home phone line and connected to somebody who’s using an Internet-based phone on the other end. The protocol allows normal phone numbers to be translated to a format that can route communications over the Internet.

An on-screen depiction of scheduled TV programs, plus the behind-the-screen applications that allow functional interactivity to occur. (Also referred to as “interactive program guide,” or IPG.)

EPGs are the front-line presentation and navigation menus that are believed to exert substantial influence over what gets watched, noticed, recorded and interacted with. In fact, in the early days of video on demand, some industry executives blamed low usage rates on poor or obscured presentation by early-generation EPGs. The theory was that the EPGs, at best, made people press too many buttons to find a desired program destination. At worst, the EPGs so obscured on-demand programming that some customers didn’t even realize they had it. Or so the argument went.

The technology behind the EPG is a relatively thin instruction set housed within the non-volatile memory of a set-top box chipset. Thus, the guide doesnt need to be loaded from external media each time the TV set is turned on. Because its memory-resident, it pops right up on the screen. Early-generation EPGs challenged even the most frugal of programmers, because the memory allocated to them was sparse.

As set-top innards have grown more muscular, so have EPGs. Newer generations feature more elaborate user functions and more sophisticated program-search options. Forthcoming iterations may feature so-called “agented search” functions that ultimately could topple the tradition of associating particular channel numbers with particular program sources. Instead, a helping hand — electronically speaking — will find and suggest the programs we want to watch.

Usage: “After roaming through the EPG, Jane rediscovered a favorite gardening program she thought had vanished from the schedule.”

A model for predicting telephone traffic, originated in 1918 by A.K. Erlang, a Danish telephone engineer. Rather than designing phone switches around peak traffic times — an enormously expensive proposition — Erlang wrote a model that accounted for the wildly erratic nature of telephone traffic (this was before people sat on phone lines for hours with their computers.) One Erlang equals 3,600 seconds of talking.

The language and physical configuration of a local area network (LAN) that interconnects multiple PCs, printers, servers, or other devices. Chances are if you look behind your office PC to see how it’s connected to the local area network, you’ll see a thick wire attached to a connector that’s slightly wider than an RJ-11 phone jack. The wire is known as “category 5,” the connector is RJ-45, and you’re on either a 10 Mbps or a 100 Mbps Ethernet connection. Ethernet is a critical enabler for most high-speed cable and DSL service connections.

The identifying characteristics of Ethernet are its data rate (in the Gigabits per second, at this point), its maximum link length (around 500 meters for coax, and 100 meters for twisted-pair copper), its media type (coax, fiber, twisted pair) and its topology (the “shape” of the network — bus, star, point-to-point.)

Ethernet also describes how interconnected things communicate. Say you’re a device that speaks Ethernet. You’re at a cocktail party with 30 other Ethernet devices. Mostly, everyone stands, sips and listens (to nothing, because no one is talking.) If you happen to blurt your packets at the same time someone else is blurting packets, your blurts collide. You stop talking, wait a random amount of time (measured in micro-seconds), then repeat what you said. So does the other person. The random wait interval helps to assure that you don’t collide again.

Usage: Ethernet was invented in 1973 by Bob Metcalfe, who founded 3Com and is one of the generally acknowledged “grandfathers of the Internet.”

A flavor of interactive television in which an interactive event is presented within the context of a
television show, rather than being invoked by a separate “menu” button on the television remote.
Synonymous with “bound application,” and a cousin of the “trigger.” Example: Voting someone “off the island,” in the case of Survivor; or firing someone, in the case of The Apprentice.

In 2004, CableLabs established a sub-group within its OpenCable effort, named ETV, and tagged it as an effort to insert interactivity into shows playing on the fielded base of digital set-top boxes. Cable industry aficionados tagged it as a sort of competitive retort the “red button,” an easy-to-use enhanced TV control offered within the BSkyB satellite TV service in the U.K.
Usage: The big example of ETV in 2005 was ABC’s “Lost,” which showed up in interoperability tests and set a milestone for mainstream content going interactive.