计算机专业时文选读之二十一

Home automation technologies

X10 Automation: Lighting, Climate, Security, Home Cinema and Beyond

When it first appeared in 1978, X10 became the standard in home automation technology. Using conventional home electrical wiring, X10 transmits digital packets through up to 256 compatible devices on a single power circuit. A control centre for an X10 system may be a standalone hardware unit or a PC running Linux or Windows. Remote controls and keypads can also be used to control light dimmers, TVs, VCRs, security alarms, door locks and surveillance equipment.

With no specialised wiring required, X10 is an affordable and reliable beginning to any digital home project. For around $250, an X10 starter kit usually contains PC and hand-held remote controls as well as modules for two appliances, two lamps and a ceiling-mounted light. To use a module, you simply plug it into a power socket and then plug the appliance into the module. The appliance is then controlled via an infrared remote control or a power-point control module such as a keypad or PC adapter. Once the software is installed, the system can be run from a Windows, Mac, Linux, OS/2 or Amiga computer. A wide selection of freeware applications for use with most X10 controllers are available online.

Universal Plug and Play (UPnP) — Networking the Home with Microsoft

X10 is essentially a remote control system for your home, limited to on, off and dim commands. In an attempt to create “intelligent” appliances that communicate via a home network, Microsoft launched their Universal Plug and Play (UPnP) technology in 1999. UPnP offers Ethernet connectivity to household appliances. These can range from lighting dimmers and climate control systems to security and audiovisual appliances. This means, in theory, that any networked Windows PC can control UPnP devices around the home (Windows ME and XP have native support for UPnP. A free upgrade for Windows 98 is available from Microsoft). It also means that you may eventually have remote access to do things like record a TV show on your home VCR via a Web browser. Unfortunately, it also means your household appliances are open to the possibility of being hacked or hijacked!

Although slow to be adopted by manufacturers, some recent UPnP devices such as standalone media players have emerged. Version 2 of the UPnP protocol is in development. This is expected to be more widely implemented than its predecessor by incorporating support for technologies such as IPv6 and .NET services.

xAP

Likened by some to UPnP, but with a smaller overhead, xAP is a network protocol designed to be independent of operating system and programming language. Although available to any mode of transmission, it is currently only implemented via serial port or Ethernet connections. The goal of xAP is a lofty one—to provide interconnectivity between all household devices including lights, telephones, Hi-Fi units, heating systems and computers. Although in its infancy, xAP has a dedicated developer community and may emerge as a contender in the future of home automation.

Jini—Networking Home Appliances with Java

If Java is more your thing then Sun Microsystems' Jini technology can network any device with a Java Virtual Machine over Ethernet, Firewire or HomeRF (a proprietary radio frequency wireless networking technology). Although it has the backing of vendors such as Sony and Philips, Jini remains within the realm of Java programmers prepared to build their own interfaces and hand-code appliance drivers.

时文选读

家庭自动化技术

X10自动化：用于照明、气候、安全、家庭影院等

当 X10在1978年首次出现时，它就成了家庭自动化技术的标准。X10利用常规的家庭电力线路，给单一电力线路上多达256个兼容的设备发送数字包。X10系统的控制中心可以是独立的硬件设备，也可以是运行Linux或Windows的PC机。遥控器和小键盘也可以用来控制调光器、电视、录像机、安全报警器、门锁和监视设备。

X10没有专门的连线要求，所以它是任何数字家庭项目廉价且可靠的开端。一个X10基本套件大约250美元，通常包括PC和手持遥控器以及控制两个装置的模块、两个灯泡和一个安装在天花板上的灯。使用这种模块时，你只需将它插入电源插座，然后将装置插入该模块即可。通过红外遥控器或电源点控制模块(如小键盘或PC适配器)控制该装置。软件一旦装上了，就能在Windows、Mac、Linux、OS/2或Amiga等计算机上运行。可以在线选择多种免费应用软件，供大多数X10控制器使用。

通用即插即用( UPnP)——将家庭与微软联网

X10基本上是家用的遥控系统，局限于开、关和明暗调节的命令。微软为了创建能通过家庭网络进行通信的“智能”装置，在1999年发表了通用即插即用(UPnP)技术。UPnP提供了以太网联接家用设备。这些设备包括从调光器、气候控制器到安全装置和音像设备。从理论上讲，这意味着任何一台联网的Windows PC机能控制家庭中的UPnP设备(Windows ME和XP天生就支持UPnP，Windows 98可从微软公司获得免费的升级)。这也意味着你最终能通过Web浏览器远程做这样的事：遥控家用录像机录下电视剧。同时，这也意味着你的家用装置有可能被黑客攻击或劫持。

虽然( UPnP)被制造商采纳的速度很慢，但最近出现了一些UPnP设备，如独立的媒体播放器。UPnP V2尚在开发之中。由于该版本包含了对IPv6和.NET服务等技术的支持，可望比其以前的版本有更广泛的应用。

xAP

有人将 xAP比作UPnP，但它的开销较小。xAP是设计独立于操作系统和编程语言的网络协议。虽然它能用于任何传输模式，但目前只是通过串行口或以太网联接实现。xAP的目标很高——连接所有的家用设备，包括照明、电话、高保真音响、供暖系统和计算机。虽然xAP尚处于幼年，但它已有了一个热心的开发者社团，在将来的家庭自动化中有可能成为竞争者。

Jini——用Java将家用设备联网

如果你喜欢 Java，那么Sun公司的Jini技术通过利用Java虚拟机，能在以太网、火线、或HomeRF(一种专有的射频无线联网技术)上连接任何设备。虽然它已得到诸如Sony和Philips等公司的支持，但Jini仍只在准备编制自己的接口和手编设备驱动程序的Java程序员中流行。