Cable-TV industry advances its expertise in hybrid networks, products and services

Cable-TV industry advances its expertise in hybrid networks, products and services

George Lawton

Sponsored by the California Cable-TV Association, the 1994 Western Cable show exhibited the industry`s advancements in hybrid fiber/coaxial-cable networks and in new customer services, such as cable telephony and video-on-demand. Featuring worldwide leadership in cable-TV, telecommunications, and information services and products, the December show attracted more than 18,000 people to Anaheim, an increase of 25% over the previous year.

Exhibitors and attendees demonstrated considerable interest in the cable-TV architectures that are expected to handle future customer services. In this regard, cable operators seem to be settling on modified versions of the hybrid fiber/coaxial-cable architectures they have been developing during the past decade. Telephone providers have also begun to realize that hybrid networks make sense for their own needs, and are beginning to deploy them commercially.

Show exhibitors presented diverse versions of hybrid fiber/coaxial-cable networks. Some vendors, such as Northern Telecom Inc. in Nashville, TN, have created a complete product line they will sell themselves. Other vendors announced partnerships in which the members bring different strengths to the alliance.

The cornerstone

Northern Telecom announced its plunge into the cable marketplace at all service levels. The company has generated an entire platform for video, voice, data and personal communications services using its own technologies. At the show, they unveiled Cornerstone, a line of hybrid fiber/coaxial-cable network-access products that will be available this year. Like other proposed hybrid architectures, the Northern Telecom system brings fiber out to 500- to 2000-home subscriber nodes and then uses coaxial cable for the home connection.

To provide voice communications, the Cornerstone network employs cable-TV`s 5- to 40-megahert¥subsplit to deliver telephony to the headend and the industry standard TR-303 and TR-008 interfaces for telephone switch connections. For data communications, Cornerstone modifies any of the 2-MH¥bands on the coaxial line to create a 1.5-megabit-per-second bidirectional channel for a subscriber. It will also support 10-Mbit/sec unidirectional data links for multimedia services.

For the future, Northern Telecom is working on an ambitious network architecture that is being spearheaded by researcher Jack Terry. The system replaces the passive taps used in traditional analog coaxial networks with low-power active taps. This replacement improves the performance of the digital signals delivered to the home by limiting the distance the digital signals travel between the fiber node and the tap. The analog signals then only have to travel from the active tap to the television set.

Terry`s scheme also proposes to put the digital signals on a fiber that is independent of the analog fiber. This scheme reduces the cost of adding digital capacity because the cost of transceiving digital signals over fiber using today`s commercially available technology can be as little as 1/10th the cost of analog.

Initially, it involves bringing the fiber carrying the digital information to the existing analog node and inserting a single band of perhaps QPSK, 16-QAM or 4-VSB modulation. Over time, this scheme is expected to further subdivide the system into smaller areas by extending the digital fiber past the line extenders.

Hybrid partnerships

Several companies have formed partnerships to provide all the necessary components to implement hybrid fiber/coaxial-cable networks. For example, First Pacific Networks Inc. in San Jose, CA, has teamed up with Ericsson Components, a division of Ericsson Inc. in Richardson, TX, to roll out a platform for telephone services. First Pacific has expertise in integrating hybrid networks for video, voice and data applications. Ericsson is adding its switched telephone network skills.

Another alliance involves Scientific-Atlanta Inc., Sun Microsystems Inc. and Siemens Components Inc. in the development of the Immxpress hybrid fiber/coaxial-cable network. In this partnership, Scientific-Atlanta is providing its cable-TV knowledge; Sun, its video server technology; and Siemens, its telephone technology and systems integration experience.

Other vendors displayed their new additions to the hybrid network arena. Philips Broadband Networks Inc. in Manlius, NY, showed its Diamond Net Optical/RF Mainstation. The device transmits signals to small nodes. A single unit can receive optical signals, convert them into radio-frequency signals and then amplify them onto a coaxial-cable network. The unit accommodates deep fiber penetration and passive optical networks.

Still other cable operators are exploring new television services to provide revenues that are not government regulated. For example, home shopping, video-on-demand and other interactive services are all potential sources of unregulated income. Under current regulations, cable operators can only charge a modest increase for supplying new television channels.

However, some cable operators doubt these new services can bring in the promised revenues. At the Western Cable Show, John Malone, chief executive at Tele-Communications Inc., the world`s largest cable company, spoke about the results of a consumer trial the company conducted in Colorado. He said true video-on-demand services generated only $8 to $9 per month in incremental revenue. These revenues were approximately the same for a near video-on-demand trial run during the same time.

Near video-on-demand services, however, are less expensive to implement. To deliver these services, a cable operator puts a movie disk in a special laser-disk player that can generate four or more video streams. True video-on-demand services mandate an expensive video server to provide a dedicated video stream to each home. Malone said it might be difficult to justify economically true video-on-demand services and the required infrastructure until the company devises new revenue generating services.

But TCI and other companies are still planning to deploy more fiber. Near video-on-demand services and networks might be less complicated to build in the headend; but in the field, TCI will be deploying fiber to carry hundreds of digital channels per system.

The only factor deterring TCI from its expansion plans has been that the cost of digital technology has not dropped as fast as anticipated. Malone said the prices the company initially negotiated were based on volume deployments, but high actual costs have put future deployments on hold. He added, "In the short run, I don`t think we can exactly predict what this will cost us. In the long run, I am a believer." q

George Lawton is a freelance writer based in San Francisco.

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