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HTINews Article

Home Plug and Play for Consumer Electronics
Submitted by Kurt Kyvik, Intellon

Everyday products operating together to make life a little better. That's what Home Plug and Play(TM) (HPnP(TM) is all about. It is an industry specification describing the way in which consumer products will cooperate with other products. HPnP is all about easy to use products offering security, money savings, and convenience.

Home Plug and Play Features:

• Industry generated specification open to use by all.

• Targeted to enable mainstream retail market for networked consumer products.

• Designed to be transport protocol independent.

• Spans many sectors, ensuring diverse product offerings.

• Defines a subsystem hierarchy so products can be designed independently.

In the past, home automation has consisted of niche products discovered by persevering hobbyists. Linking these islands of automation has been the purview of the custom installer. The average custom installation occurs in a 5,000 square foot house - hardly a mass market. Home Plug and Play is an industry specification designed to break down the barriers of cost and complexity. Consumers will be able to purchase a variety of interoperable Home Plug and Play products at familiar retail outlets.

Home Plug and Play is a win for retailers who will be able to offer a broad array of interoperable components and systems. Since Home Plug and Play ensures interoperability, the retailer has greater flexibility in presenting products on the show floor. Components can be marketed as systems or broken out in product sectors, such as video "accessories". Retailers can also forge stronger relationships with customers by offering integrated packages or installation services. Home Plug and Play products will be delivered through several channels depending on the background and business of the manufacturer. Companies developing the Home Plug and Play Specification and designing products now, already have strong relationships with the builder community, dealer/installers, electronics retailers, and large discount chains.

The reason Home Plug and Play is happening now is because of confluent trends and technologies. Sufficient home networking technology is available upon which to build an interoperability specification. Home Plug and Play leverages the tremendous effort that has already gone into such protocols as the EIA-600 CEBus Standard and IEEE 1394. The companies that first got together as the Home Plug and Play team focused not on the product details, but instead on the big picture issues that prevented a mass market for connected products in the home.

The other trend indicating the time is right for Home Plug and Play is the market itself. Both the push and the pull are present. Mainstream manufacturers are introducing networked products. Instead of trying to sell "home automation", manufacturers are having greater success selling simple extensions of their normal product lines - these products just happen to communicate. Home Plug and Play is the next logical step to get one manufacturer's "extended" products to cooperate with another1s products.

Home Plug and Play is an interoperability specification that defines high-level interactions between products. The lingua franca for these product conversations is CAL, the Common Application Language of the CEBus Standard. Selecting a common language is a small part of the product interoperability problem. The real work entails defining a subsystem hierarchy, specifying a means for sharing resources, and establishing common installation techniques.


One of the most important new concepts introduced by Home Plug and Play is "loosely coupled systems". This concept is a recognition of the fact that light switches don't generally communicate with thermostats. Lighting products tend to understand each other and work well together. Likewise, environmental control products tend to interoperate. Inside these subsystems the components are tightly coupled. The subsystems themselves are loosely coupled by simple announcements of the house's desired operating state. For example, when the homeowner returns at the end of the day and disarms the security system, an announcement is broadcasted that tells the subsystems to operate according to their own design and set-up for an occupied house. The lighting subsystem controller uses this house state information to directly control the lighting components in its tightly coupled subsystem. Individual light modules can remain very simple and low cost. The lighting controller, which might be a PC or a dedicated product, provides the next higher level of complexity and integration. Loosely coupled systems help manufacturers bring products to market by allowing products within a subsystem to be created without detailed knowledge of every potential product in the house.

Although the hierarchy of subsystems is an important enabler of the retail market, it alone is not sufficient. Manufacturers still need to be able to design compelling applications that are detailed and product-sector specific. To meet this need, Home Plug and Play gathers together all of the commands needed by many individual products. In CAL these commands are grouped functionally into Contexts. The

Home Plug and Play specification includes Contexts for Audio/Video, Computers, Energy Management, Lighting, Security, Telecommunications, and User Interfaces. This dictionary will grow as new product categories are added.

Home Plug and Play also addresses several thorny problem areas that have inhibited home systems in the past. Device installation is one such problem. Many techniques and opinions have been proffered about the best way to install products. These strong opinions usually follow from a host of assumptions about consumer aptitude, availability of installation tools, and even physical access to the device being set up. Home Plug and Play specifies a small set of procedures and management commands that provides structure and commonality to the installation process.

Here's a brief description of other topics dealt with by HPnP:

• Publishing and subscribing to resources: Some products provide information or resources for other products in the home. A good example is time. HPnP defines how this information is published and how other products find and use the resource.

• Grouping products: geographical zoning, scenes, and even multi-family dwellings are covered.

• Scheduling: One of the great utilities of networked products is to be able to schedule events. HPnP provides detailed data structures and editing techniques.

• Locking: One of the tools that HPnP provides is the ability to lock all or part of a device for some operations. Locking is important, for example, to prevent a product from interfering with a complicated schedule creation that is taking place over the network.

• Security: Applications require several levels of security commensurate with the protection needed and the complexity that can be afforded. At the more robust end of the spectrum are utility energy management systems and security systems, usually requiring both authentication and encryption. Convenience products typically need only simple anti-spoofing protection. HPnP addresses security in detail.

The HPnP Specification is being completed by the Interoperability Technical Committee of the CEBus Industry Council (CIC). After being initiated by Honeywell, Intel, Microsoft, and Thomson Consumer Electronics, HPnP has grown to be embraced by dozens of companies contributing to its completion. Home Plug and Play is expected to be released as a provisional specification on March 31, 1997, giving manufacturers a chance to build and test products in a "plug fest" environment. Feedback from the plug fests will be incorporated in Release 1.0 available August 1997. Products are currently under development by CIC members.

The CIC is an industry based, non-profit, membership organization established in 1994 by those companies adopting and implementing the EIA-600 CEBus Standard as their technology platform for providing a uniform method of giving products network features. For more information on the development of the Home Plug and Play Specification or on the Interoperability Technical Committee, contact Mike Coffey at the CIC by phone: (317) 545-6243, or E-Mail: cebus-staff@cebus.org.