IP Edge Door Controllers: The Future of Access Control
By Jason Barton, EIT
Network cameras and recorders have been around the security world for a few years and are beginning to take over a significant portion of the market share, especially since the price has decreased and the technology has improved. However, on the access control side, development has been slower. Recently, the emergence of IP Edge Door Controllers has sparked interest and caused changes in access control hardware that hasn’t been seen in decades.
Edge Door Controllers use a standard network connection to communicate to the access control server. They provide connections for the card reader (CR), door position switch (DPS), request-to-exit device (REX) and electric lock (EL). They have a small amount of internal memory so they can still operate during the rare occurrence of a network outage. They also take advantage of Power-over-Ethernet (PoE) that many network switches now have built-in. The IEEE 802.3af specification used for PoE allows a maximum of 15.4 watt (W) load to be ran over a Category 5E cable up to 100 meters. Specification IEEE 802.3at (which is slated for release within the next year), also called PoE Plus, will allow up to a 30W load on 1 pair inside the Cat5E and perhaps up to a 60W load on 2 pair.
One of the primary advantages of using an Edge Door Controller is the reduced cost associated with the cable required. Most access control systems require four separate multi-conductor cables (or a bulky composite cable that combines all of these into one jacket) to be routed from the intelligent field panel (IFP, usually located throughout the building in a data room) to the components located at the door: one each for the CR, DPS, REX and EL. The cost associated with pulling one cable as opposed to four is substantially lower, not to mention the cost of the cable itself since the price of copper continues to rise. Also, on new construction, the cabling can be included in the cabling contractor’s scope of work instead of the security contractor’s scope of work. This solution will be less expensive and provide the customer with a neater installation because the cable can be routed and terminated with all the other network cables throughout the building. Additionally, Edge Door Controllers eliminate the need for IFPs so there is no need for security enclosures on the wall in the network rooms.
Companies including HID, S2 and Amag have Edge Door Controllers available today. However, there are disadvantages associated with using these devices. They provide enough current (by means of PoE from the network switch) to power the card reader and motion detector (if needed) with somewhere between 550mA and 350mA (@ 12VDC) left for the electric lock. Herein lies the first problem. A typical 12VDC electric strike pulls somewhere around 350mA when engaged (unlock time) but a typical electric mortise lockset can pull as much as 750mA with an inrush current as high as 1.5A. Some of the more popular electromagnetic locks (maglocks) pull somewhere around 750mA. Therefore, the power constraints associated with the current PoE standard is one limitation of Edge Door Controllers. PoE Plus should solve most of these issues when network switches begin incorporating it later next year.
A second problem with Edge Door Controllers involves distance limitations. Edge Door Controllers are under the same distance limitations we are accustomed to in the network world. The controller can be no more than 100 meters from the network switch. Typically this is not a problem if IDF rooms are spaced throughout the building to accommodate this limitation, but in some security applications this could become an issue. There are products on the market that act like a network repeater, allowing network and PoE signals to be routed as much as 300 meters which provides one solution for this problem.
Another disadvantage of using Edge Door Controllers is, currently, there is no way to use PoE to power a fail-safe lock and have it drop power in case of a fire, which is required by code for maglocks and locks on stairwell doors. The only way to incorporate a fail-safe lock is to power it separately from the Door Controller. This requires a separate cable and power supply which would have to be integrated with the fire alarm system to release the lock during a fire. This negates some of the advantages of the Edge Door Controller. Future technology will allow for a mountable inline device in the network rack which will provide this capability. Currently, no such device like this exists.
Edge Door Controllers are a new technology, and like many new products on the market it will go through some growing pains. They offer many advantages over the traditional way of doing access control, but current limitations are preventing use in certain applications. With the emergence of PoE Plus and if/when the integration with the fire alarm system happens, I.P. to-the-door will become more of an industry standard, much like what we’ve seen with network cameras in recent years.
Jason Barton, EIT, is a security consultant with EDI. He can be reached at jbarton@ediltd.com.
