Motorola is due to demonstrate set-top boxes that combine cable and off-air signals. The prototypes will be show at The Cable Show in Las Vegas. Based on a specification currently in development through the CableLabs consortium, the hybrid approach could reduce the requirement for cable carriage of local broadcast channels.

Ironically, the inclusion of integrated off-air tuners could give cable operators an advantage when it comes to negotiating retransmission agreements with broadcasters. Broadcasters can currently either force carriage of at least one of their channels under federal “must-carry” rules, or they can negotiate retransmission on commercial terms.

The hybrid approach could save capacity on the cable networks for must-carry channels and enable operators to avoid paying broadcasters for retransmission, while allowing access to the full range of local television signals, including high-definition broadcasts.

Such an approach has also been used by satellite broadcasters to enable reception of local channels.

Motorola is due to demonstrate two prototypes at the annual cable industry show: one with an integrated off-air tuner and the other with a port that accepts an antenna in a USB stick. Future developments will include dual-channel off-air tuners, enabling picture-in-picture viewing and the ability to watch one channel while recording another.

The boxes read channel identification information contained in the ATSC digital terrestrial television broadcast signals, substituting off-air reception for local channels. This is designed to enable seamless channel switching through a single electronic programme guide.

Meanwhile, the American cable industry is promising to deploy OCAP, the Open Cable Application Platform for interactive services, by the end of 2008.

A derivative of the MHP standard developed in Europe, the Java based OCAP has been long in coming. Cable operators had previously promised to roll out OCAP by the end of 2006, but deployments to date have been limited to technical and market trials.

The slow uptake of OCAP has been a factor in limited adoption of interactive television on cable in the United States.

The Cable Show will feature a pre-convention conference dedicated to OCAP and will feature developments in its annual technology showcase.

The Cable Show, formerly known as The National Show, takes place from 7-9 May at the Mandalay Bay Convention Centre in Las Vegas.