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| PoE (Power over Ethernet) |
| by Mr. Henry Pang, Technical Manager, FingerTec Worldwide |
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| The Basic Features of PoE |
| PoE (power over Ethernet) is a technology to supply power to power devices (devices consuming power from PoE) via Cat5e Ethernet cable (normal LAN cable), together with communication data. |
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| For Cat5e Ethernet cable, there are 4 twisted pairs, and only 2 pairs are in use to transfer data. Meanwhile the other 2 pairs are remaining useless. Therefore the PoE technology fully utilizes these 2 pairs in Cat5e Ethernet cable, as power supply cable. But then the power devices must integrate with PoE IC module so it can receives power by PoE. |
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| PoE complies with 2 IEEE standards, which are 802.3af (since 2003) and 802.3at (since 2009). The reason of standardization is to provide guideline to manufacturers to develop their products to fit into the IEEE standards, then to power up by PoE.
The major difference of 2 standards is 802.3at provides greater power, voltage and current than 802.3af does. Therefore the 802.3at PoE can support devices with higher power consumption.
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| Property |
802.3af (802.3at Type 1) |
802.3at Type 2 |
| Power available at PD |
12.95 W |
25.50 W |
| Maximum power delivered by PSE |
15.40 W |
34.20 W |
| Voltage range (at PSE) |
44.0-57.0 V |
50.0-57.0 V |
| Voltage range (at PD) |
37.0-57.0 V |
42.5-57.0 V |
| Maximum current |
350 mA |
600 mA per mode |
| Maximum cable resistance |
20 Ω |
12.5 Ω |
| Power management |
Three power class levels negotiated at initial connection |
Four power class levels negotiated at initial connection or 0.1 W steps negotiated continuously |
| Derating of maximum cable ambient operating temperature |
None |
5°C with one mode (two pairs) active |
| Supported cabling |
Category 3 and Category 5 |
Category 5 |
| Supported modes |
Mode A (endspan), Mode B (midspan) |
Mode A, Mode B |
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| The PoE supports 2 types of working models: |
Mode A (endspan)
Endspans are Ethernet switches that include the power over Ethernet transmission circuitry. Endspans are commonly called PoE switches. Endspans are normally used on new installations or when the switch has to be replaced for other reasons (such as moving from 10/100 Mbit/s to 1 Gbit/s or adding security protocols), which makes it convenient to add the PoE capability. |
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| Avaya ERS-5520 switch with 48 power over ethernet ports. |
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Mode B (midspan)
Midspans are power injectors that stand between a regular Ethernet switch and the powered device, injecting power without affecting the data. Midspans are used when there is no desire to replace and configure a new Ethernet switch, and only PoE needs to be added to the network. |
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| The Most Common Applications |
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| Applications of PoE include: |
a. Networking communications/data transfer: Cisco, Linksys, D-Link
b. Security cameras, Network webcams or IP camera: Sony, Panasonic, Synel
c. Network Intercom / Paging / Public address systems and hallway speaker amplifiers
d. VoIP phones
e. Wall clocks in rooms and hallways, with time set using Network Time Protocol
f. Biometric 2-in-1 system: Suprema (D Station and T2), Bioscrypt L1
g. Card 2-in-1 system: Suprema (XPass)
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| The similarities of the applications: |
a. Requires continuous/uninterrupted data transfer for video and voice streaming, entry-exit monitoring.
b. Require continuous/uninterrupted power supply.
c. Low power consumption (except item F and G).
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| The Pro & Cons of PoE |
| Pro |
Cons |
| 1. |
1 data cable (Cat5e cable) to carry out data transfer and power supply. |
| 2. |
Save cost of cablings and material. |
| 3. |
Safe and easy installations – Not involve any dangerous voltage or power source. |
| 4. |
PoE can supply power to the devices over long run of cable without power loss. |
| 5. |
Cat5e cable is common and cheaper. |
| 6. |
Cat5e cable can transfer data speedy up to Gigabits per second |
| 7. |
No more concern about the local variance of AC power standard and plugs. |
| 8. |
Direct injection by battery arrays to keep all devices power on even during outages. |
| 9. |
Symmetric distribution of power source, and decide point of power source after cabling work is done. Not a must to locate near a power source. |
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| 1. |
Extra cost for PoE midspan or endspann switches (Click https://www.nextag.com/cisco-poe-switch/products-html to see prices of various branded PoE switches) |
| 2. |
Only applicable to low power consumption devices (less than 25watt) |
| 3. |
Require special “injector or splitor” in case the devices consume more than 25watt (click https://www.phihong.com/html/poe.html to see PoE midspan provides more than 30watt of power) |
| 4. |
Devices must comply with standard IEEE 802.3af/at (added with special PoE IC module) |
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| Relationship of PoE and FingerTec products |
| 1. |
For FingerTec models, currently we can only apply PoE IC module into TA200Plus. Cost to add PoE module is USD15 per module. |
| 2. |
Other models can only support PoE Converter (see https://accessory.fingertec.com/poe-converter.html for details). |
| 3. |
For FingerTec PoE converter (a.k.a. Splitter) can only supply power for:
a. 5VDC, 700mA
- sufficient for models: AC100C, TA100, TA100C, TA100TC, TimeLine 100)
b. 12VDC, 300mA
- sufficient for models: AC900, R2, Q2i, TA200 Plus, iKiosk 100, iKiosk 100 Plus, Kadex, MKadex
- insufficient to power on door lock system.
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| 4. |
However we can use PoE injector with more than 30watt outputs (see https://www.phihong.com/html/poe.html) to support FingerTec door access model and door lock system. However 1 unit of PoE injector can only apply to 1 entrance (maximum 2 terminals and 2 locks). Cost of PhiHong PoE Injector starts from RM200 per unit. Similar installation concept with current AdapTec AC. However the PoE injector provides less security with our next coming AdapTec Plus (using encrypted Wiegand signal to unlock door). |
| 5. |
Cannot apply to models without proper Cat5e jack: R2, iKiosk 100, Kadex and MKadex. |
| 6. |
Factory is currently doing study about implementation of PoE with their access control models. However they noticed the heat sinks from PoE affect the terminal itself. The reason is the plastic (ABS) housing of the terminals accumulates heat and damage components/circuit on board. |
| 7. |
Unsecured power supply for door lock system:
a. All door lock wires connect into the terminal itself. A smash to the terminal or dismantled of terminal turn off the door lock system immediately (assuming customer does not link up to any alarm system).
b. Unplug of the Cat5e cable of the terminals cut off power to the terminal and door lock system.
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| The Market Demand of PoE: |
| According to a study about Power Over Ethernet: A Global Market Demand Analysis, it showed: |
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Steady grow of both PoE midspan and endspan
a. PoE Midspan: 4.95 million ports (2006), 8.1 million ports (2007) and 11.75 million ports (2008)
b. PoE Endspan: 140 million ports (2006), 175 million ports (2007) and 205 million ports (2008)
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| Remark: the statistical data of PoE depends on how many ports because each unit PoE switches comes with a number of port e.g. 24 ports, 64 ports etc. |
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| In the reports, we also noticed: |
| 1. |
The need for 24v, 12v or 5v would rule out powering by Endspan Switches which are only capable of IEEE standard 48v and 15.4 watts maximum.
a. FingerTec models are either 12VDC or 5VDC, and can fit into PoE Midspan. |
| 2. |
Midspan PoE is capable of mix and match voltage and protocol styles and will be preferred for many of these new applications including: IP Based Network Security Cameras, RFID Tag Readers, IP Thermostats, Print Servers, Bar code Scanning, Alarm Systems and Sensors, Security Access controls including badge readers, Smoke detectors, Stage lighting, Industrial Clocks and time keeping, Lighting controls and In-Flight Entertainment systems.
a. Suprema and Bioscrypt are using PoE technology for their access control system, however they do not provide any technical information about their PoE.
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| 3. |
The marketplace for both Endspan and Midspan PoE is healthy and will continue to grow in future years. This growth is based partly on a wide range of additional new products coming which will be powerable via PoE technology. Many of these devices will be better suited to Midspan powering due to variances in voltage or wattage requirements or the smaller number of units required on the End User's Network. LAN Power Systems, as a major technology innovator in the PoE market, is committed to long-term participation and continual development of new PoE products which incorporate the key elements of Flexibility, Simplicity and Value. |
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| References: |
| The Basic & Technology of PoE |
1. https://en.wikipedia.org/wiki/Power_over_Ethernet
2. https://www.anixter.com/AXECOM/AXEDocLib.nsf/(UnID)/PowerDsine_SecurityFlyer.pdf
3. https://www.infocellar.com/networks/new-tech/PoE/PoE.htm
4. https://www.digikey.com/Web%20Export/Supplier%20Content/Coiltronics_4036.pdf?redirected=1
5. https://www.transition.com/TransitionNetworks/Resources/en/PDF/PowerOverEthernet.pdf
6. https://www.bb-elec.com/tech_articles/Power_Over_Ethernet.asp
7. https://www.midspans.com/pages/whypoe.php
8. https://www.nextag.com/cisco-poe-switch/products-html
9. https://www.phihong.com/html/poe.html
10. https://www.midspans.com/pdf/Phihong_2010_PoE_Catalog.pdf |
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| The Demand of Market to PoE |
1. https://www.articletrader.com/technology/power-over-ethernet-poe-global-market-demand-analysis.html
2. https://www.lan-power.com/eagle_tech/PoE_mkt_adoption.htm |
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