From state to state, rules and regulations vary regarding the installation, servicing, maintenance and operation of low voltage electronics used to power security systems. In some states, the regulations are stipulated at a local level while others maintain state-wide codes. Power solutions for life safety and fire installations are subject to similar varying regulations but additionally must meet a variety of national standards and federal laws.
Within the video surveillance category new power technologies such as Power over Ethernet, which is based on information technology standards, is unregulated and needs only to comply with industry standards such as the IEEE 802.3af (PoE) or IEEE 802.3at (PoE+). PoE is restricted to 13 watts (12.95 watts), and the PoE+ can supply up to 25.5 watts to power additional devices such as outdoor cameras, infrared illuminators, etc. In some cases the PoE may require additional approvals such as those for access control applications (i.e. UL294B).
Power for remote devices
PoE is a recognized power solution around the world that provides a safe and efficient way to deliver power to remote devices such as IP video cameras over the same Ethernet CAT5 (or higher) structured cable that carries data. It’s a simple plug and play connection that allows security professionals to take advantage of the inherent benefits networked systems offer.
An important note is that the deployment of conventional power devices are subject to issues such as correct power distribution, ground loop, voltage regulation or crosstalk. PoE fed through the same cable with Ethernet data reduces the possibility of these and other issues related with analog installations. And if the network connection is lost, powered devices on the edge may remain operational thus maintaining security.
Midspans and endspans
PoE sources are available as midspan or endspan devices that may carry a variety of agency listings and approvals. In a typical IP surveillance network, a camera communicates with a video IP server through a network switch. A midspan which is placed between the switch and the camera injects power and passes through video data, whereas an endspan incorporates the power sourcing equipment and switch in one unit. Midspans typically offer both PoE and PoE+ standards for PTZ and IR cameras that require more power than conventional IP cameras.
More advanced midspans can be managed and monitored locally and remotely with the ability to reset individual ports. This helps ensure that sufficient power is maintained for connected devices and provides the ability to perform maintenance on individual ports without shutting down all of the connected devices. Advanced midspans are also designed to minimize the risk of damaging non-compliant PoE devices if accidentally connected to power sourcing equipment. For added versatility, manufacturers like Altronix also offer extenders for midspans to increase cable length in increments of 100 meters, as well as PoE adapters to power conventional 12VDC IP devices.
PoE and IP devices are being deployed at a rapid pace as they offer a wide range of features and functionality with extreme efficiency, and the price points for these devices continue to decrease as they continue to gain widespread acceptance.
