CableLabs has kicked off an initiative that will result in a new cable interface that will allow digital set-tops to receive off-air digital broadcasts.

Though still in the formative stages, the effort will aim to deliver those digital signals "seamlessly" and complement the video and other information already being delivered to the set-top via the cable plant.

The Louisville, Colo.-based cable R&D house has yet to issue an RFI or RFP on the matter, but, according to CableLabs President & CEO Dr. Richard Green, the resulting specs will likely consist of hardware and software components.

The hardware element will include silicon-based tuners - a technology that has improved significantly over recent years. The software portion will seek a seamless way to integrate how off-air and cable plant-delivered signals enter the box. Although OCAP (OpenCable Application Platform), a set-top middleware specified by CableLabs, could have a role, it won't necessarily be a requirement for the initiative, Green said.

CableLabs also will explore multiple implementations of the technology. In addition to a version that can be baked into set-tops, CableLabs will also take a look at how off-air tuners can be retro-fitted with legacy boxes.

Green would not provide any specific timelines for the project, other than to say that CableLabs has started work on the spec, is discussing options with a range of manufacturers, and hopes to have something issued "as soon as possible."

The announcement comes about two years ahead of the broadcast digital transition, which is slated for Feb. 17, 2009. Additionally, as of Thursday (March 1, 2007), all TVs that can receive off-air signals must be equipped with digital tuners, according to an FCC mandate. In accordance with that and the coming 2009 deadline, a spate of organizations - including the National Cable & Telecommunications Association, Consumer Electronics Association and National Association of Broadcasters - just launched a new Web site - DTV Transition - to help consumers navigate the analog-to-digital migration.

"From a technical point-of-view, it's a good time for this," Green said of CableLabs' latest initiative.

Although cable's satellite competition already offers a digital off-air option, there are other possible implications for the CableLabs initiative.

While not considered a primary driver, it could give operators another option for delivering local broadcast TV signals to customers. Such an option could grow in importance as broadcasters and cable operators continue to cross swords over testy retransmission negotiations.