Extending ethernet capabilities
Hailed as a watershed innovation when first standardized in 2003, Power over Ethernet (PoE) offers a way of supplying electricity to network devices over standard Ethernet data cables. A convenient and affordable way to power up network devices such as wireless access points and security cameras, PoE eliminates the need for separate electrical power lines to each device.
In fact, PoE has been instrumental in fuelling the deployment of networked applications, according to Daniel Feldman, who is chairman of the technical subcommittee on PoE and PoE Plus at the Ethernet Alliance. “There wasn’t a lot of deployment of IP cameras, wireless LAN access points or IP phones before PoE, which was created partly to enable these applications to exist,” he says.
The Ethernet Alliance is a non-profit consortium of system and component vendors, industry experts and university and government professionals, committed to the continued expansion of Ethernet technology, which is poised to become dominant in a world of all-IP migration.
Using already existing Ethernet cables for transferring not only data and voice but electrical power as well, greatly reduces installation and maintenance costs associated with security installations.
“PoE allows you to locate devices anywhere you want without needing a certified electrician to install an AC outlet,” says Feldman. “Another main benefit is that PoE enables power supply backup via the Ethernet switch.”
It also hinders intruders from shorting a circuit to kill surveillance cameras while they haul away the goods. And, because the UPS (Uninterruptable Power Systems) can be much larger with PoE, doors, for example, can be kept secure much longer in the event of a major power outage.
Coupled with the booming demand for security monitoring worldwide, the freedom granted by PoE has made cameras appear in every conceivable location. In addition to cameras, the market for access systems, RFID tracking, biometric identification, fire detectors and other security equipment continues to expand, benefitting from the PoE technology. Several access control equipment suppliers now offer readers, controllers and soon to be released, locks based on PoE.
PoE is well positioned to bring additional power to enable the convergence and integration trends in the security market,” says Feldman. Numerous features and capabilities are being added to security systems and the camera is evolving into a comprehensive integrated security tool. With PoE, the camera market is ready to add even more features, such as speakers, microphones, sensors, door-lock interfaces and fire detectors.
The drawback, however, of more and more sophisticated security devices is that these require more power than the existing PoE standard is able to provide. Therefore, work is underway to standardize the next version of PoE, called PoE Plus.
More wattage with PoE Plus
The current standard (known as 802.3af) can deliver a maximum of 15.4 watts, which was determined based on the amount of power required by IP phones and the CAT3 cabling infrastructure prevalent in 1999. As PoE Plus will permit 25.5 watts, the scope of camera applications grows. Speakers, heaters that prevent moisture build-up and door-lock supplies are other power-heavy features soon within reach. In addition, more power may further facilitate access control by being able to power mechanical door openers.
“I have no doubt that PoE will be built into all kinds of security applications,” says Feldman, who points out that the opportunity to use Ethernet cables for recharging of batteries in a host of devices will be another future benefit.
When upgrading an existing installation from PoE to PoE Plus, the easiest way is to use a “Midspan”, a stand-alone, plug-and-play device that resides between an ordinary Ethernet switch and the terminals. It’s particularly useful at present, since the new standard has not yet been ratified and is therefore not built into vendors’ switching equipment or end devices such as cameras.
In looking ahead, Feldman points out the huge, untapped potential for PoE in the residential market, saying that the entire home may rely on PoE for access control, security, locks, cameras, WLAN, modems, even indoor lighting, as solid-state lighting powered by PoE is on its way. But he adds, “Many people don’t feel comfortable using PoE in home applications.”
When it comes to safety, concerns have been addressed by ensuring that power is only applied to devices that have been detected and verified as PoE-compliant.