POE or 802.3af

It is very expensive to install the required dedicated power for security and network devices. To reduce cost and increase reliability a new standard has been defined, POE or 802.3af. Most security and network devices can be redesigned for the 12.95 watts power limit. Just to give an idea of the cost savings Purdue University estimated saving of between 350 and 1000 dollars per device by eliminating the electrical outlets required by other technology.

Parking operations can benefit from this as well. True, mains power is conveniently located in the gate housing but we have found this to be a major source of really nasty electrical noise. Typical gate motors and ticket spitters produce substantial surges that can disrupt the typical card reader. Because POE powers all of the electronics associated with the card reader from an isolated source system reliability is greatly enhanced. The real beauty is one Cat5 cable carries both power and data. That is the kind of simple clean and cost effective engineering we promote.

Advantages and Disadvantages of Power Over Ethernet

The major disadvantage to Power over Ethernet is the cost of the network equipment. Proper planning reduces the impact of building a Power Over Ethernet infrastructure. By incorporation of the POE specification into the system requirement for replacement equipment this disadvantage is mitigated.

The advantages include lower cost, greater reliability and improved performance. The installation cost is reduced because only one common cable (CAT-5) is needed for power and data. Further the actual termination of that cable is standardized with a common and inexpensive connector. Reliability is enhanced because the power is delivered from a common point, eliminating ground loops and power disruptions. Performance is improved because of increased data circuit capacity over conventional 485 and current loop technology. Further using 802.3af compliant supply equipment allows the network administrator to monitor and control power to each device.

How does a company implement Power over Ethernet?

To convert an existing installation to PoE is relatively easy. A Midspan power injection device is placed between the existing network switch and the Cat5 cable going out to the Powered Device or PD. These injectors are available in a variety of configurations and port counts. A new installation might want to invest in a Network Switch with 802.3af compatibility. We have a Level 3 switch with 12 powered ports that would meet that requirement. Email us for more details.

An important consideration is the overall power budget. The 802.3af specification allows for 12.95 watts to be drawn from the Power Source Equipment or PSE. You must do the math to make sure that you do not exceed the PSE manufacturer's total power with all of your devices connected.

KMS is the first to offer Power over Ethernet Card Access.

According to Senior analyst, Marianne D'Aquila from Venture Development Corporation "KMS is on the forefront of Power over Ethernet configured security and parking solutions. They are the first company we know offering a Power over Ethernet card access system."