The Promise of PoE: Just Connect and Go
PoE over coax holds so much promise — especially in retrofits. SDM examines how and why it can be a shortcut to IP.
Power over Ethernet (PoE) over coax started as an extension to PoE over UTP cables, but it has grown into much more. Today Ethernet data streams and power can be passed over UTP cables and transported over coax. This opens up the opportunity to offer IP over existing infrastructure — bringing significant time and material savings for integrators — and giving end users the realistic possibility of IP in situations where it might not otherwise be on the table. SDM looks at what developments are being made with the technology and what details integrators should consider to make it a successful installation solution.
“For decades, most analog-based CCTV cameras have been connected to recording and control equipment via common coaxial cable. In fact about 80 percent of analog cameras were installed with coax and most of those cable runs are less than 750 feet. Today, a lot of surveillance systems are going in with IP cameras connected via UTP and fiber to network recording and control equipment. That means if you want to retrofit or migrate to IP from analog CCTV, for starters, you have to re-cable using UTP —unless you tap into PoE and Ethernet over coax (EoC),” says Guy Apple, vice president, marketing and sales, Network Video Technologies (NVT), Menlo Park, Calif. “The elegance of the solution is its simplicity of design and application. The technology enables more installers to approach an IP migration project with a new set of financial and installation options.”
It is important to consider that PoE over coax allows the end user to choose when they would like to install IP equipment, because the migration can be done incrementally, Apple says.
“If one was to install an entirely new UTP network infrastructure, the project would be done in one pass, but legacy coax can be migrated from analog cameras to IP cameras in the time frame chosen by the end user. Because the technology takes advantage of the re-use of legacy coax cable, and reduced labor, it can be as much as 25 percent of an IP upgrade,” he predicts.
Frank Haight, vice president of marketing, Communication Networks (ComNet), Danbury, Conn., describes the technology as a “shortcut to IP.”
“I think the best ‘shortcut to IP’ that can be considered is the choice of Ethernet and PoE over coax. The technology is now that simple. Ethernet data and power over one coax; just connect and go,” Haight says.
Working with existing resources is a key feature in a strong retrofit market like the United States.
“PoE over coax is mostly designed for markets with existing coax infrastructure, so for the United States and more developed regions it is more common in retrofit installations, observes Olivia Dumanovsky, marketing specialist, Pakedge Device & Software, Foster City, Calif.
“A few benefits of PoE over coax would be that it is much less expensive because less labor is needed; it’s also more convenient in retrofit situations and you won’t need to rip out as many walls or building materials,” Dumanovsky explains.
A number of different manufacturers offer options for PoE over coax today, increasing the possibilities for integrators.
James Rothstein, executive vice president, Tri-Ed Distribution, Woodbury, N.Y., observes that the offerings, which include everything from basic to more sophisticated, come with common benefits of cost and time savings.
“When you look at the cost savings and efficiency of not having to rewire — in addition to getting the benefits of IP — PoE over coax can be a very attractive option both for the dealer in terms of time and cost and for the end user in terms of cost and increased capabilities.”
Rich Mellott, director of product and program management for Stanley Security Solutions, credits advancements in Ethernet adapters for growing usage of the solution.
“The ability to transmit Ethernet and PoE over coax has increased in acceptance within the security industry due to highly sophisticated Ethernet adapters that allow for increased transmission data rates of up to 100mbps at distance greatly exceeding network cabling standards,” Mellott explains. “Maintaining data rates of 100mbps allows for successful deployment of high-definition megapixel IP cameras, voice-over-IP (VoIP) emergency communication equipment, IP access control systems and many other life-safety devices that are continuously emerging.”
Ronnie Pennington, national accounts manager, Altronix Corporation, Brooklyn, N.Y., agrees that the development of Ethernet adapters affords systems integrators with a cost-efficient and easy means to transmit video, data and even PoE over coax. He emphasizes some of Ethernet adapters’ key features in “Highlights of Ethernet Adapters” on page 96.
Available power, distance, and signaling are also key areas that have advanced, Haight shares.
“With the standardization of the IEEE802.3at (PoE+) standard, the amount of available power increased from 15.4 watts under the IEEE802.3af standard to 30 watts using two unused pair in a Category X cable. So now the power that goes out over the UTP or coax along with the Ethernet stream can support higher-powered devices such as wireless access points, PTZ security cameras and other devices that need higher power to operate,” Haight describes.
Ethernet and PoE distance have always been a trade-off between bandwidth (10/100 Mbps) and the ability to overcome the resistance/dissipation inherent in the copper cable and deliver the correct amount of power to the device at the end of the run, according to Haight.
“The Cat 5 family of UTP cables has a maximum accepted distance of 100 meters for 100 Base TX Ethernet transmissions,” he adds.
The last factor is signaling. Signaling or a “handshake” occurs when the PoE device that requires power (also called a powered device or PD, such as PoE IP camera) sends a request to send power and how much power to send to the device that injects power on to the cable (power sourcing equipment or PSE, such as a mid-span injector, PoE Ethernet switch or PoE media converter).
When asked what helped ensure success of PoE over coax installations, everyone SDM spoke with universally emphasized checking the quality of the coax.
“Coaxial cable quality matters. Good quality coax that is free from imperfections and splices is important,” Haight advises.
Because in many of the applications, the cable is existing infrastructure, the integrator needs to understand the capability of the transmission system and the system layout, says Ed Davis, vice president, marketing, American Fibertek (afi), Somerset, N.J.
“Checking product performance specifications is extremely important,” he says.
Integrators should consider the type of coaxial cable installed to confirm that it is RG59U/18 AWG or better, Peffington advises. “In addition, integrators should be sure to consider whether the devices they plan to install require PoE (12.95w) or PoE+ (25.5w) PoE over coax adapters to operate,” Peffington says.
“One more important factor is the length of the run because of the voltage drop associated with this,” he adds.
Power is key, and there are differences in power consumption related to the attached devices that should be considered before selecting your PoE components, cautions Stanley’s Mellott.
“Standard analog devices will require an IP conversion before they can transmit via PoE. Fixed analog cameras, for example, have an average draw of 5W, while a PTZ camera is 15W and a PTZ with heater/blower may be as much as 35W. Considerations based on power consumption are required to allow for proper success in your design,” Mellott emphasizes.
According to Mellott, there are two differences in PoE switches for your power budget:
• Power budget per port
- This allows you to design a solution that, no matter how many devices of a class or different classes you have, will power them if it meets the port power rating. (This is a more expensive switch.)
• Total power budget per switch
- This type of switch requires you to be very aware of what types of devices you have on the switch or will add to it; otherwise, your total budget may exceed the switch capacity. (This is a more cost-effective switch.)
- Example A: A switch that has a budget of 30W would support a maximum of four Class 2 devices, but only two Class 0 or Class 3 devices.
When selecting a product that is advertised to support PoE, it should be clarified if the product is compliant to the 802.3af or 802.3at standard, according to Chad Szekeres, national sales manager, Nitek, Rolling Meadows, Ill.
“Many products do not support the networking PoE standards. Some manufacturers sell or supply plug-in power transformers that are needed to power and/or create PoE for the system. Other products are marketed as PoE pass-through, which by standard is considered an ad hoc system. An ad-hoc system connects to a PoE switch and simply passes the PoE through the system to the connected PoE edge device.
“For a product to truly be standards compliant, the units must be able to be powered from power sourcing equipment (PSE) such as a network switch or PoE inserter and must also be able to supply PoE to the connected edge device but only if the connected edge device is a powered device (PD). This communication allows the edge device to be detected by the power sourcing device and allows the edge device to negotiate the amount of power required to operate,” Szekeres says.
Naturally when you want to leverage the existing infrastructure and provide the benefits of IP, there are some limits to what that can provide from an IP point of view/bandwidth, but it is a viable, sufficient option in many installations, says Tri-Ed’s Rothstein.
“Integrators just need to understand the length of the run and the project’s specifications, as well as the technology’s capabilities,” Rothstein observes.
It is all very important so they can deliver what they want to deliver — the full benefits of an IP system and the appropriate bandwidth — which is a greater possibility today with solutions like PoE over coax, the “shortcut to IP.”
Highlights of Ethernet Adapters
The numerous benefits provided by IP video surveillance and security/access systems continue to fuel the migration from analog to network infrastructure. But not every user is ready to replace their coax infrastructure with Ethernet cabling due to the associated labor and material costs. With the introduction of Ethernet adapters, systems integrators now have a cost-efficient and easy means to transmit video, data and even PoE over coax. Here are some of the feature highlights of Ethernet adapters:
- Estimating and project layout time is much faster.
- Labor and material savings can add up to as much as $4,000 for a 16-camera system.
- They transmit IP signals over coax five times the maximum distance of Ethernet cabling without the need for repeaters.
- They can transmit high-quality digital and analog (composite) video simultaneously over the coax.
- One technician can install the Ethernet adapters versus the need for two technicians to pull new cable.
- It’s easy to add more cameras with the transmission of multiple IP cameras over a single coax cable.
- Compact 1U rack mount receivers with four and 16 ports make installation fast, easy, and extremely cost-efficient.
Many integrators are embracing the installation of Ethernet adapters to migrate their customers to an IP platform. The bottom line is that Ethernet adapters enable your technicians to work more efficiently while reducing installation costs and increasing profitability. — By Ronnie Pennington, Altronix Corporation
SDM asked, ‘What are the Top 3 Benefits of PoE Over Coax?’
1.Significant labor and material savings resulting from using existing coax infrastructure when compared to removal of the coax and installation of new Ethernet cabling.
2.Maximizing and preserving the initial investment in coax infrastructure.
3.The ability to transmit video, data and power up to 1500 feet, or five times the maximum Ethernet distance, without a repeater (when using certain PoE over coax offerings including the plug-and-play eBridge1CRT receiver and transceiver kit offered by Altronix, that accommodates multiple IP cameras and devices over a single coax cable or one IP camera with composite video and data simultaneously). — By Ronnie Pennington, Altronix Corporation
SDM asked, ‘What are the Top 3 Benefits of PoE Over Coax?’
1.Reduced installation time and material cost. In most analog-to-IP-video migrations a coaxial cable infrastructure already exists to support the analog video system. Ethernet over coax with PoE allows for the conversion of technology without removing the previously installed cable infrastructure and the labor cost associated with the removal. Utilizing the coax cable eliminates the purchasing and installation of network cable.
2.Less disruptive to your clients. Whether your client is a hospital, school or office building, relocating employees, students or patients while the technicians remove ceiling tiles to route cables is a disruption to their day-to-day business. When using an existing coax cable there is no need to route cables, move ceiling tiles or relocate personnel.
3.Overcoming distance limitations and reducing network devices. The IEEE 802.3ab network cabling standard limits cable distances to 100 meters (328 feet). Historically, coax cable runs will average 545 feet, with many as long as 1,300 feet or more. Ethernet over coax with PoE allows for transmitting 100mbps and PoE up to 1,500 feet between devices, eliminating the need for mid-span power injectors and network switches. — By Chad Szekeres, Nitek
SDM asked, ‘What are the Top 3 Benefits of PoE Over Coax?’
1.The top three benefits of PoE over coax all truly relate to cost reduction. In many applications where analog cameras are being replaced by IP cameras, the existing coaxial media is still in place. Ethernet over coax eliminates the cost of new fiber optic or additional switches/repeaters to extend distance, as well as the labor to install it. It also eliminates the need for AC power at the field location. That saves labor and the need for electrical outlets in the vicinity of the each camera location. This enables a simplified installation as the coax can be used for both Ethernet data and power.
2.By reusing the coax for data and power, the 100-meter Cat 5 cable distance limitation is overcome. Distances for Ethernet data and power can be increased to greater than 250 meters between the field location and switch or power sourcing equipment (PSE). The overall benefit, again, is reduced cost.
3.Central power management/backup. Because the cameras at the field location are no longer powered from a local supply, they are immune from power failures. For example, if you have a power failure in a remote parking facility, you do not lose your surveillance capability. Also, during times when there is not activity, PoE-powered field devices can be remotely set to conserve power. — By Frank Haight, ComNet
Looking to the Future
Dumanovsky shares that integrators considering using PoE over coax should keep in mind that running things over coax is “basically like a band aid.”
“It is usually done because it’s too expensive or too difficult to run an Ethernet cable. Also, going over coax is usually a step backwards and is mostly for convenience. In the future, everything will run off Ethernet cables,” she explains.
When that happens, Dan Dunar, associate product manager, Honeywell Cable & Custom Electronics, Pleasant Prairie, Wis., suggests that opting for Cat 6 will offer several advantages. The most significant difference between Cat5e and Cat6 with respect to PoE is improved power transmission.
“Many camera manufacturers specify Cat 5e as the minimum cable requirement, but Cat6 has larger conductors and consequently lower DC resistance. This leads to lower voltage drop and longer power transmission distance. Lower resistance also limits heat generation. Excessive heat buildup degrades a cable’s ability to transmit data, which can severely compromise video quality. This effect would present itself similarly to the way a scratched DVD ruins a movie. One may see artifacts, skipped frames, or even a complete suspension of audio/video. The big difference, of course, is that DVD movies usually don’t have security and lives at stake,” Dunar explains.
The signaling or “handshake” that happens in a PoE demand application is:
1. PSE device detects devices that need power (PD).
2. PSE determines power required.
3. Requires “handshake” or acknowledgement from PD and determines when to turn on power.
4. Detects when device has been disconnected.
5. Detects when to remove power.
Stanley’s Mellott offers PoE classifications to consider when supporting your devices:
• Class 0 — 15.4 watts at PoE port; .44 to 12.95 watts at device
• Class 1 — 4.5 watts at PoE port; 3.84 watts at device
• Class 2 — 7.5 watts at PoE port; 6.49 watts at device
• Class 3 — 15.4 watts at PoE port; 12.95 watts at device
• Class 4 — 34.2 watts at PoE port; 12.95 to 25.5 watts at device
Note: Class 4 devices were added with the new 802.3at standard.
“The more we as an industry can reuse existing cabling, the less earthly resources are needed, not to mention that dealers can provide clients with upgraded systems at very competitive costs,” writes SDM columnist Dave Engebretson as he explores alternative cabling methods such as PoE over coax in the Security Networks column: “Saving Millions of Feet of Coax”