A digital headend made by Motorola Broadband, which serves as the “central nervous system” of all cable digital video implementations that use Motorola’s conditional access and encryption system. That means 90% plus of Comcast’s footprint, and about 15% of Time Warner’s footprint (post-Adelphia). The DAC applies digital video security to just about all related services, and links to the billing system.

As competing technologies go, the DAC is sort of like Scientific-Atlanata’s “DNCS.” When people talk about “the duopoly,” they’re usually referring to these two products.

A license, issued by CableLabs to consumer electronics manufacturers, for the bare nuts and bolts of channel descrambling through a CableCard. Pronounced as the letter “D” followed by the word “Fast.” A more comprehensive license, CHILA (see definition) also exists. DFAST is a subset of CHILA, containing details about the technology that moves protected bits over the pins of a CableCard, into a “host device.” So far, host devices are digital TV or HDTV sets, but other devices with CableCard slots are surely coming.

A chief difference between DFAST and CHILA involves equipment compliance: CHILA stipulates initial and ongoing CableLabs tests as well as the inclusion of OCAP (OpenCable Applications Platform); DFAST defines one CableLabs certification followed by manufacturer self-certification.

Usage: “This announcement will allow the collective innovation of the consumer electronics industry to directly benefit cable operators and cable consumers.” – CableLabs CEO Richard Green, announcing the availability of the DFAST licensing agreement in 2003.

The central nervous system of Scientific-Atlanta’s digital video headend. Job one for the DNCS is to apply conditional access (see definition) to digital set tops. But the DNCS conducts several other critical activities, stretching from back office to plant to set tops. On the back-office side, the DNCS filters information to and from functions like customer billing. It also shares its encryption work with QAM modulators, and talks regularly to connected set-top boxes about how and when to send guide or control data.

As related products go, the DNCS is like Motorola’s “DAC,” for Digital Addressable Controller.” When you hear people talk about “the duopoly” in digital video scrambling, they’re usually talking about those two products.

Voice, video, data or other traffic that moves from a central point; i.e., the headend or central office, outward toward homes and businesses. In cable, downstream frequencies reside between 54-860 MHz, typically. Information traveling from an in-home device toward the headend or central office rides on the upstream signal path.

The splicing of one hunk of digitized video into another hunk of digitized video — like a digital ad into a digital TV show. DPI, as an industrial term, grew out of the Society of Cable Telecommunications Engineers’ Digital Video subcommittee, and straddles two technical standards: ANSI/SCTE 30 and 35.

Splicing a digital ad into a digital program requires two things: A cue trigger, and a splicer. Cue triggers are the digital equivalent of the “doodly-doot” sounds we used to hear, in the old days, which triggered a local ad to over-ride the Ginsu knives ad. They consist of a short stack of packets that identify the splice point for a local ad, usually originating with digital program networks or content aggregators.

The splicer does what it implies: It watches the river of MPEG-2 video bits blasting into a headend from the satellite feed. When it sees the cue trigger, it lifts the correct ad off a local ad server, and cuts it in.

A software tool inside the DOCSIS 1.1 (and later) cable modem and PacketCable specifications that adjusts bandwidth “on the fly” and according to the needs of a particular broadband service. Maybe it’s to upgrade someone’s cable modem speeds for the weekend, as part of a special “turbo button” promotion. Or maybe it’s to set things up for VoIP service, which needs bandwidth without delays more than it needs bandwidth in big chunks. D-QoS is advancement upon “QoS.” People pronounce it as the letter “D” then “kwoss,” as in, rhymes with “pea sauce.”

Chips that store information by writing it to electronic addresses, then reading it later when required. The “dynamic” part means it holds the information only when the power to its “host” unit is on. “Random access” means the addresses can be read at any time, in any order, at the same speed. DRAM and other memory chips are generally grouped by storage capacity, in Megabytes or Gigabytes. Personal computers rely heavily on DRAM, but it’s also used in set-top boxes, cable modems, and in-home electronics equipment. The kind of RAM memory that doesn’t forget when the power is off is called NV-RAM, or “Flash” memory (the “NV” is short for “non-volatile.”)

Usage: In set tops, people generally talk about memory in twos — flash, and DRAM. They’ll say “8 by 16,” for instance, to mean a set top that contains 8 Mb of flash memory, and 16 MB of DRAM.

The technologies and applications that protect copyrighted material from unauthorized duplication and distribution. In a sense, DRM is an outgrowth of conditional access — it extends usage rights to reflect additional business rules and applications. DRM has at least four industrial constituents, each with different goals:

Copyright holders: “Protect my stuff from theft”
Distributors: “Protect stuff moving over my network so well that I can distribute fresher stuff faster”
PC/IT: “Use my DRM, all other DRM is crap”
Consumer Electronics: “Don’t let copyright holders dictate the functionality of the devices we make”

And now this from the Department of the Obvious: These four stakeholders are giant industries. Their goals often clash. Tell your kids to go to law school and specialize in DRM. You’ll grow old well.

The best-case scenario for DRM is that it becomes a mechanism to build and enact new business models for premium content, so that content can play within a “trusted domain” of cable-ready consumer devices. That could mean portable video players that plug into a digital set top or digital cable ready TV, and accept a big, fat, protected download. The “protected” part is the DRM.

Technologically, DRM is mostly about copy protection (see definition). The cable industry’s angle is to develop a “trusted domain,” which extends the cable plant to additional devices in the home — in a secure and “trusted” way. (Trusted by copyright owners.) Those extensions could be to PCs and “home media centers,” or to portable video players, as two of many examples. What’s needed to make it happen are the interfaces to third-party DRM providers.

The headend/control part of the linkage with an embedded cable modem, for use in situations where modems are nested inside devices such as a set-top boxes, or digital cable-ready TVs. A clunky term, to be sure, but not one that will likely ever see the light of day, in a consumer sense.

Hey. Could be worse: The inventors of DSG originally wanted to call it “DOCSIS Out-of-band Gateway,” or “DOG” for short. Sort of seems like an insult to dogs.)

DOCSIS is the subject of a 35-page CableLabs specification. If that sounds daunting, here’s a simplified way to imagine the workings of a DSG: Imagine a cable-ready HDTV that contains an embedded cable modem for purposes of two-way cable communications. (This could also be a digital video recorder, or a game console, or a portable video player — or anything else you can imagine as a cable-connected consumer device.)

Say this HDTV set is under the control of a customer who just initiated a video on demand session. The request is routed to the embedded cable modem, which passes it upstream, over the cable plant, to the headend. There, it goes where traffic from cable modems always goes: To the cable modem termination system. The CMTS looks at the incoming packets. “Aha,” it says. “You’re a session-set-up for a set top. Over there, please.”

It passes the VOD initialization request to the DSG, which talks back and forth with the set-top controller, which talks with the VOD controller, to set-up the session. The confirmation, and session details, move back to the embedded cable modem and HDTV in reverse order. Back at the couch, everything seems the same. Maybe the VOD title arrives a little faster, but faster in a way that isn’t obvious, except that it seems to work really well.

This pattern repeats for everything that needs to occur, or is planned to occur, between cable-connected devices and the servers and routers that handle information flows. Masterminding the flows is the DSG.

In a diagram, the DSG attaches to the CMTS on one side, and other background controllers (such as existing set-top controllers) on the other side. It’s partly a router, partly a proxy server, mostly an intermediary. Its primary role is to manage the business policies that describe how, and under what circumstances, different devices, with embedded cable modems, are allowed to connect.

Usage: DSG gurus are quick to point out that just because a device contains an embedded cable modem, that doesn’t mean “surf the Internet or send e-mail.” So far, DSG is strictly for the shuttling of command and control information.

A popular form of high-speed Internet service delivered over telephone networks using otherwise fallow spectrum above 4 KHz.

DSL went from laboratory term to near-household name in the space of about five years, as telephone providers across the world staged aggressive deployments. DSL is the most prevalent form of residential high-speed Internet access in the world; the slight market dominance of cable-delivered DOCSIS Internet service in the U.S. is the aberration. See ADSL, ADSL 2+

A device used in telco digital subscriber line networks to combine, then route, incoming DSL traffic to the Internet. In telco data configurations, the DSLAM allows router port sharing. In a sense, a DSLAM is to DSL networks what a CMTS is to cable networks.

Without a DSLAM, each DSL line would require its own router port — a hugely expensive proposition. By combining multiple DSL inputs into one composite output, telcos can save on the capital expense of the routers. But it also means that DSL is a shared network — at least from the DSLAM north, to the Internet backbone.
Usage: Often located in the telephone company central office, DSLAMs concentrate DSL subscriber lines into a high-speed Internet conduit.

A computing integrated circuit and its associated programming, specifically designed to deal with digitized signals that started off as analog signals. Used widely in telecommunications equipment. Voice processing, echo canceling, compression and modulation/demodulation techniques all run on DSPs. They’re fast, and they’re programmable, making them particularly suitable for broadband communications.

Usage: In modern digital consumer electronics devices, DSP chips manage bass, treble, reverb, and surround sound processing.

A consortium, formed in 1993, of mostly European broadcasters, equipment manufacturers, network operators and regulatory bodies, focused on the development of open standards for digital video, including wireless and mobile transmissions. Missions include interoperability, flexibility, and attention to reasonable and non-discriminatory handling of intellectual property rights (IPR).

Usage: The DVB Project says its work “has proven the value and viability of pre-competitive cooperation in the development of open digital television standards.”

A subset of the European DVB, focused on writing a framework for advanced interactive TV applications that run on digital, MPEG-2-based video networks. Successful enough that the North American cable television industry, and specifically CableLabs, based a significant portion of its OCAP effort on the work of the DVB-MHP. Its sort of the industrial version of “if you can’t beat’em, join’em.”

Usage: The engine behind DVB-MHP is the Java Virtual Machine (JVM).

The machine that ate television. Or at least seemed destined to do so when it first stormed the TV landscape around 2000. (Also known as “personal video recorder.”)
DVRs seem innocent enough: they’re typically about the size of a videocassette recorder, and accomplish some of the same functions VCRs are known for, such as recording TV programs for later viewing. In the digital world, this practice is increasingly known as “time-shifting.”
But the comparisons stop there. DVRs use computer-like hard disks, not videotape, as their storage medium, and unlike VCRs, they’re outfitted with digital video processors that perform various feats of digital magic unto TV signals. DVRs make it much easier for users to record programs, with some of them going so far as to allow one-touch recording of all instances of a favorite TV show that might pass by. They permit recording by program title, by the appearance of a favorite actor, even by the name of a sports team.
There’s one thing that DVRs bring that strikes fear into the hearts of TV industry captains: the ability to fast-forward past recorded content. Translation: they make it pretty darn easy to omit commercials from your life. Advertisers, agencies and the networks that depend on them have conducted serious hand-wringing over the specter of a nation outfitted with ad-skipping technology, and a consensus solution remains elusive.
While many users can and do rocket past commercials using DVRs, though, many find equal delight in the ability of the machines to effect pause and rewind commands on “live” TV. (We say “live” in quotes because DVRs actually spit out TV that’s slightly delayed from the actual broadcast stream. It takes a second or two to encode/decode.)
Many a hot dinner, urgent telephone call and civil conversation have been preserved because of the ability to pause a TV show in mid-scene and return to it later. Lately, DVRs have gone from standalone retail devices to nicely integrated components within holistic cable and satellite TV services. The difference is substantial. A cable customer who buys an off-the-shelf DVR from the local Best Buy will encounter a programming guide and navigational functionality that is quite different from that delivered by the cable provider. A cable-integrated DVR supplied by a cable operator, in contrast, features the same navigation, guide and menu functionality the customer is (presumably, at least) accustomed to.

Usage: “The DVR really doesn’t do anything positive for those of us who are in the content business.” – NBC Universal chairman and CEO Robert Wright, speaking at the 2005 National Show

A method of increasing the carrying capacity of an optical network by packing more colors of light into a single strand of fiber. Signals are sent on different optical wavelengths, or colors, of light, thus squeezing more bandwidth out of the fiber.