The Federal Communications Commission's recent decision to explore the use of powerlines as Internet on-ramps could legitimatize technologies that are easier to install than CAT5 solutions and are more secure, interoperable and reliable than wireless networking.
The "no new wires" technologies network over power, phone and cable TV wiring; increase job turnaround; eliminate objections to running wires; and reduce support calls. Integrators are deploying these alternative technologies when wireless will not work. "We're technology-agnostic," says Charles Stanton, president of Manhattan Home Networks, New York. "We'll use powerline or HomePNA technology if it works in a customer's wiring and meets their needs."
According to tests by Digital Connect Lab engineers on multiple products from Linksys, Corinex and other manufacturers, alternative networking technologies provide a true plug-and-play experience, physical security, as well as encryption, interoperability and consistent performance. They protect the bottom line, support remote-management services and can be deployed as a stopgap and augmented by wireless once the issues shake out.
The HomePlug 1.0.1 standard set by the HomePlug Alliance supports transmission speeds up to 14 Mbps over ordinary powerlines. Communications are limited to the powerline that devices are plugged into, making it hard to eavesdrop from another location. The standard's 56-bit DES encryption also aids security.
Performing site surveys to identify separate powerlines and provide bridges between them are revenue opportunities. Determining the connection quality between outlets is easily accomplished using a receiver/transmitter pair like the Corinex Diagnostics Kit, available for less than $70. The technology's freedom of movement is rivaled only by wireless. In fact, powerline technology is a wireless enabler that eliminates running a CAT5 cable to access points. "Sometimes we will use alternative technology to help with wireless deployments," says Stanton.
Most HomePlug devices Lab engineers have tested are second only to HomePNA devices for their plug-and-play ease. Testing also indicates that devices from different manufacturers are completely interoperable, unlike wireless.
PHONE LINE NETWORKING
The HomePNA 2.0 standard uses two-wire phone lines as the physical layer for transmissions up to 14 Mbps. HomePNA traffic can flow simultaneously with DSL and voice traffic on the same line or on a dark line. This lets integrators form ad hoc networks between client devices in a given room by daisy-chaining them with ordinary phone line cables. While phone jacks are not as common as power outlets, HomePNA can be used to extend a network to another floor in a home. "HomePNA proved very beneficial for a customer as an alternative solution," says Jim Belske, principal at OnCall TechSolutions, Stewartsville, N.J. "He had a home and another building that his office was in. We looked into line-of-sight wireless solutions, and it became just too expensive."
Nodes must be less than 500 feet apart, which is fine for most residences. In fact, the technology is deployed even in large hotels. Drivers for the few HomePNA devices that require them are included in Windows XP. Installation requires no more effort than a toaster.
NETWORKING ON COAX
Corinex has combined the HomePlug protocol with cable modem silicon to produce devices that use cable TV coax as the network's physical layer. It combines the advantages of HomePlug 1.0.1 with a 700-meter range and the ability to filter networking signals. The product is well-suited for multiple-residence dwellings.
The only caveat is that the technology uses the same band as cable modems, so a notch filter should be used to prevent possible interference. This technology can be used to bridge PBX extensions or electrical legs, especially between floors or buildings.
POWERLINE NETWORKING DEVICES
Lab engineers tested a suite of powerline devices from Corinex, Vancouver, British Columbia, for Web browsing, video-chat, surveillance and wireless network access. To test the router and client solutions, databases were replicated over a powerline network and the Internet via VPN. In more than a month of continuous use, the devices worked flawlessly.
To connect PC clients, Corinex offers the Corinex Powerline Ethernet Wall Mount Adapter and the Corinex Powerline Ethernet Adapter, both at $70. The wall-mount adapter is the size of a power transformer and plugs directly into a wall outlet. A CAT5 cable connects the adapter to the client to complete installation.
The Powerline Ethernet Adapter is a desktop-style network bridge. Its power cable plugs into an outlet, and the included CAT5 cable connects it to a PC or switch. A button configures the port for straight-through or crossover use. Although the PC needs a working NIC, no other drivers are required. A setup wizard displays connection quality alongside the MAC addresses of HomePlug devices and can change the default encryption key.
For Internet access, integrators can connect another powerline-to-Ethernet adapter to an existing switch or router or use a Corinex Powerline Router if there is no legacy broadband router. The Corinex router ($120) was as easy to set up as most cable/DSL routers via a Web interface. In addition to typical features, it has internal MAC address and scheduled IP and Web site filtering. A built-in three-port switch enables the sale/integration of wired networking equipment. The Corinex Wireless To Powerline Access Point ($130) was also easy to set up and worked well at providing 802.11b connectivity. It simply plugs into a power outlet. Its Web interface allows encryption key configuration. It can be configured to act as a wireless client to bridge powerline network segments.
PHONE LINE DEVICES
Linksys, Irvine, Calif., has a well-rounded lineup of HomePNA equipment. For client connectivity, a HomeLink 10M PC Card ($70) and a HomeLink 10M USB Adapter ($70) were tested. When used with Windows XP clients, they require no driver disk or floppy. Drivers for other operating systems are supplied, however.
The HomeLink 10M PC Card provides connectivity to a laptop. Like most HomePNA devices, the unit features two RJ-12 connectors: one for the phone line and another as a pass-through connector. This allows integrators to daisy-chain HomePNA devices. The HomeLink 10M USB Adapter was connected to a laptop and a PC for testing. The unit, which derives power from the host's USB port, would not operate off the laptop's USB 1.0 port. It worked fine connected to a desktop with USB 2.0 ports. Linksys should explore making an externally powered version.
The HomeLink Phone Line 10M Ethernet Bridge ($200) was used to connect a PNA network to a wired network during one test, and to connect a CAT5 client to a PNA network in another. The bridge features two RJ-45 jacks that share a single port: one for connection to a PC, the other for a network switch or cable modem. The units are stackable, and multiple units can be connected to a switch to bridge PBX extensions into a single data network.
Linksys' HomeLink Phone Line 10M Router ($150) is designed for combination CAT5/HomePNA networks. It features an RJ-45 jack for a wired network and three PNA ports. That RJ-45 jack has a straight-through/crossover switch. Two PNA ports are for networking and the third has a built-in filter for a phone extension. The Linksys unit supports PPoE, provides a DHCP server, features port forwarding and a DMZ. It also can filter traffic by IP address or port, somewhat useful for PC-centric parental control.
Going a step beyond, the device can work as a sole router/gateway or alongside other routers. It supports both dynamic and static routing. Setting up the router was straightforward.
Engineers tested the Linksys HomePNA gear on active and inactive home extensions and found it easier to set up than any other networking technology. Two streams of Web-chat video were sent across a phone network with reasonable video quality; continuous audio was played across the same extension without dropouts.
The Corinex CableLAN Adapter ($123) is an Ethernet-to-coax bridge that transmits network data over coax using the DOCSIS cable modem standard. Its F connector plugs into a cable TV outlet, and the included CAT5 cable connects it to a PC or switch. A push button configures the RJ-45 port for straight-through operation with a PC, or crossover use with a network switch. No drivers are required. A utility for configuring the passphrase and displaying the MAC addresses and connection speeds of other units on the network is included. The units worked very well— engineers saw no interference with consumer-electronics devices but interaction with a PC TV tuner was noted and eliminated with a filter.
While coax jacks aren't as ubiquitous as power outlets or phone jacks, this technology experiences less line noise, and is therefore a good technology for joining floors with guaranteed bandwidth. Its 700-meter range also makes it useful for multifamily and multibuilding dwellings.