The announcement today that BigBand Networks is deploying its switched digital video (SDV) technology in multiple systems with Cox Communications – Northern Virginia, for starters – has roots in another time and place, namely three years ago in Tyler, TX.

That was when and where the two companies conducted a field trial over a 550 MHz plant using Motorola set-top boxes and a program guide from Pioneer (now Aptiv.) This was "Trial A" discussed in an article we published in March 2005, which considered switched technology as an alternative to a plant upgrade.

In an interview this week, BigBand VP and Manager, Cable Video Americas, Biren Sood said the Tyler trial was the "probably the first public disclosure" of their work with Cox. The Motorola challenge This week’s announcement from BigBand states that Cox "has begun to deploy the solution in its Northern Virginia market." That’s a Scientific Atlanta-based system. But it also states that Cox is deploying in both S-A and Motorola environments.

Given that BigBand’s switched digital technology originated within Time Warner Cable‘s predominantly S-A plant and that a lot of SDV talk lately has turned on questions of openness, that’s the more significant part of this news than the NoVA win.

"It’s a testament to the years of experience, the fact that we support open protocols, of course, and the fact that we can operate in a number of different combinations of set-top boxes, network infrastructure, conditional access environments," Sood says.

As a refresher, just how do these environments differ? Sood notes five points of divergence (S-A vs. Moto):
• Encryption (PowerKey vs. DigiCipher)
• Type of two-way network (DAVIC vs. ALOHA)
• Set-top boxes (Explorer vs. DCT)
• Client software (involving some third-party guide vendors)
• Network control system (DNCS vs. DAC)

Were any of these especially challenging? "The area that we’ve focused a significant amount of our time on was the two-way network," Sood says. "The Motorola environment is a little bit thinner, in terms of how much room they give you to operate in."

Sood also pointed to the set-top clients as the "long poles to deployment." The challenge there has been for BigBand to ensure that its switched system works "hand in glove" with software that resides on the set-top. In the box, at the edge The focus on two-way calls to mind another fairly obvious point: That applies to both overall plant and individual set-tops. The Cable-Tec Expo papers by Todd Bowen, director of digital systems at Time Warner Cable, Austin (discussed here) and Bob Clyne, Sr., VP technology at Cablevisions Systems, both mention the topic of non-responders.

Into that category go unidirectional host devices. "Any channel that is put into SDV is unavailable to CableCard-equipped (unidirectional) TVs and PVRs such as the TiVo Series 3," writes Bowen in his paper.

It’s a dilemma, but doesn’t only impact SDV. "You need two-way to offer VOD, as well," says Sood. "(Those subscribers) would have a problem accessing any switched content, but they would still be able to receive all the popular broadcast programming that is not well-oriented for a switched tier."

The take-away is that it’s fair to talk about SDV and niche content in the same breath. As for Cox, this announcement refers to an expanded HDTV lineup. In the case of Cablevision, which deployed switched video (using BigBand technology) across its entire footprint, what the consumer noticed was the availability of an additional 60, mostly international, programs.

On the topic of edge QAM modulators, a category whose summer buzz we’ve been tracking. Sood confirmed that BigBand "continues to be a very large supplier of edge QAMs in our switched digital video offerings" and said that what operators are looking for is more "deployability, stability and versatility" rather than the highest possible density.

"Sometimes density and high upconversion ratios … have some challenges in terms of being able to find contiguous spectrum on cable system plants that you can block-upconvert into," Sood said. – Jonathan Tombes

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