Identification Devices

Identification devices include card/key/barcode¹/radio frequency identification readers, keypads, and biometric² readers. As introduced in Chapter 5, access control systems can determine your identity by what you know, by what you have, or by who you are.

The most basic types of identification (ID) readers are keypads. Basic keypads are simple 12-digit keypads that contain the numbers 0-9 and ∗ and # signs (Fig. 6.1). The most desirable attributes of keypads are that they are simple to use and they are cheap. The most undesirable attribute of the keypad is that it is relatively easy for a bystander to read the code as it is being entered, and then you have been duplicated in the access control database (i.e., now two people know your code so now no one is sure if the person who used the code is really you). Also, the pizza delivery guy usually knows a code because there is usually someone in the organization who gives out his or her code for such things. This defeats the purpose of access control because now management has no idea who has the codes. Although shrouds for keypads are available, they are cumbersome and do not seem to be well accepted, and the pizza delivery guy still knows the code.

Two other variants are the so-called “ashtray” keypad, which conceals the code quite well (Fig. 6.2), and the Hirsch™ keypad, which works very well. The Hirsch keypad displays its numbers behind a flexible, transparent cover using seven-segment LED modules. Then, to confuse the guy across the room with the binoculars, it scrambles the position of the numbers so that they almost never show up in the same location on the keypad twice. This ensures that even though the guy with binoculars can see the pattern of button pressing, it will be useless because that pattern does not repeat often (Fig. 6.3). We have also found that in many organizations, there is something about the high-tech nature of the Hirsch™ keypad systems that seems to make its users more observant of the need not to give out the code to unauthorized people.

One step up the scale of sophistication from keypads are ID cards and card readers. Access control cards come in several variants, and there are a number of different card reader types to match both the card type and the environment.

Common card types include

• Magnetic stripe

• Wiegand wire

• Passive proximity

• Active proximity

• Implantable proximity

• Smart cards (both touch and touchless types)

Increasingly rare types include

• Barcode

• Barium ferrite

• Hollerith

• Rare-earth magnet

Magnetic Stripe Cards

Magnetic stripe cards (Fig. 6.4) have a magnetic band (similar to magnetic tape) laminated to the back of the card. These were invented by the banking industry to serve automatic teller machines (ATMs). Typically, there are two or three bands that are magnetized on the card. The card can contain a code (used for access control identification), the person’s name, and other useful data. Usually in access control systems, only the ID code is encoded. There are two types of magnetic stripe cards: high and low coercivity (how much magnetic energy is charged into the magnetic stripe). Bank cards are low coercivity (300 Oersted) and most early access control cards were high coercivity (2750 or 4000 Oersted). However, as clients began to complain that their bank cards failed to work after being in a wallet next to their access card, many manufacturers switched to low coercivity for access cards as well. Desirable attributes of magnetic stripe cards are that they are easy to use and inexpensive. Undesirable attributes are that they are easy to duplicate and thus not suitable for use in any secure facility.

Wiegand Cards/Keys

The Wiegand effect is named after its discoverer, John R. Wiegand. The Wiegand effect occurs when a specially made wire is moved past a magnetic field, causing it to emit a very fast magnetic pulse in response (10 μsec) to the magnetic field. Wiegand wires are placed into cards and keys in a pattern of north/south such that they create ones and zeros when read by a Wiegand card/key reader. In the early days of access control, a wiring protocol was established to accommodate Wiegand effect readers, called the Wiegand wiring scheme for card readers. Today, manufacturers refer to their proximity card readers to be wired with this Wiegand wire interface.

Barcode Cards

Barcode cards use any of several barcode schemes, the most common of which is a conventional series of lines of varying thicknesses. Barcodes are available in visible and infrared types. The visible type looks similar to the UBC barcode on food articles. Infrared barcodes are invisible to the naked eye but can be read by a barcode reader that is sensitive to infrared light. The problem is that either type can be easily read and thus duplicated; so barcodes are also not suitable for secure environments.

Barium Ferrite Cards

Barium ferrite cards are based on a magnetic material similar to that used in magnetic signs and refrigerator magnets. A pattern of ones and zeros is arranged inside the card, and because the material is essentially a permanent magnet, it is very robust. Barium ferrite card readers can be configured for insertion or swipe type. For swipe types, these are often in the form of an aluminum plate placed within a beveled surface. The user simply touches the card to the aluminum surface and the card is read. Swipe and insertion barium ferrite cards and keys are almost nonexistent today, relegated only to legacy systems. The aluminum touch panel is still common in some locales.

Hollerith

The code in Hollerith cards is based on a series of punched holes. The most common kind of Hollerith card is that which is used in hotel locks. Some Hollerith cards are configured such that their hole patterns are obscured by an infrared transparent material. One brand of Hollerith is configured into a brass key (Fig. 6.5). Hollerith cards are not commonly used in secure facilities.

Rare-Earth Magnets

An extremely rare type of access credential is the rare-earth key. The rare-earth magnets are set in a pattern of four wide by eight long and each can be positioned so that north is pointing left or right, making a pattern of ones and zeros. Such keys are very difficult to duplicate and are suitable for high-security facilities, although their cost is high because each key must be handmade.

Photo Identification Elements

Access cards grant access and identification cards provide visual evidence that the bearer is authorized to be in the area. Identification badges can have many visual attributes, including a photo of the bearer, a logo of the organization (not necessarily a wise thing), the bearer’s name, and a color scheme that may identify areas where the person is authorized. Sometimes, a color or code may designate if the bearer is a contractor or vendor.

To help verify the authenticity of the card, it is common to laminate a holographic overlay that provides a visual indication that the card has not been tampered with.

Some organizations use separate access cards and identification cards, but most have combined the two functions into a single credential.

Multi-technology Cards

As organizations grow, it is common for some employees to need to travel to multiple offices and facilities where different card technologies may be used. There are three solutions to this problem. One solution is to have the traveling employees carry a different card for each facility they visit. Another is to convert the entire organization’s access control system to a single card standard, which can be expensive. Finally, technology can come to the rescue by creating a card that contains codes that are readable by two or more access control systems. Multi-technology cards can include magnetic stripes, Wiegand, proximity, and even smart cards all in one card. Implantable chips can provide access to very high-security facilities with an assurance that the credential has not found its way into the wrong hands.

Card Readers

Card readers have been configured in a number of different ways. Early card readers were of the insertion type (Fig. 6.6). These were prone to getting dirty and thus reading intermittently. Swipe readers came next (Fig. 6.7). These were easier to keep clean and more reliable. These mostly eliminated the problem of chewing gum and coins being inserted and were also easy to use. However, reliability was still a problem.

Proximity card readers date back to the early 1970s, and they continue to evolve (Fig. 6.8). Reliability issues have been virtually eliminated for all but intentional abuse. Proximity card readers have been designed for many unique environments, including normal interior walls (for mounting to single-gang electrical box) (Fig. 6.9) and door frames (mullion readers) (Fig. 6.10). There are also long-range readers for use in car parks and garages so that the user does not need to roll down the car window and be exposed to the weather (Fig. 6.11).

Proximity cards and readers work by passing a handshake set of radio frequency signals (traditionally in the 60- to 150-kHz range). Basically, the reader is always transmitting a low power signal through one of two antennas in the card reader. When a card comes into the radio energy field, the radio frequency energy is picked up by one of two antennas on the card and is used to charge a capacitor. When the capacitor voltage reaches a critical level, it “dumps” its energy into an integrated circuit (chip) on the card, which is programmed with a unique card number. The chip also has a radio frequency transmitter, and it transmits the unique card number through a second antenna on the card. All this occurs in milliseconds. When the card reader picks up the transmission from the card, it passes the card number to the reader input board of the access control system, where a grant/deny access decision is made based on the facility code and card number, which together make up the unique card number code, and the day and time of presentation of the card.

Newer proximity cards and readers use smart-card technology that can also receive, store, and process information from the card reader back to the card, allowing more complicated transactions. For example, the card can be used like a credit card to purchase food in a vending machine or gas at a gas pump. The card can store a history of transactions, such as where the user has gone and with what readers he or she has interacted. Some transactions may be unknown to the user such that it is possible to track a user’s position in a facility at any given time or for other special purposes. One exotic access control credential is the implantable chip. Only slightly larger than a grain of rice, the chip can be implanted in a user’s arm and can provide access to high-security areas. These chips have been implanted in agricultural animals and pets for many years to help track an animal’s health and locate its owner when lost. It is the closest thing to biometrics (Fig. 6.12).

Other Field Devices

These include electrified locks, door position switches, request-to-exit devices, and gate operators. Electrified locks are discussed in detail in Chapter 7.

There are a nearly infinite number of types and applications of electrified locks. This is one of the areas that set the master designer apart from the journeyman. It pays to learn electrified locks exceptionally well because many codes stipulate how certain types of electrified locks can be applied. Also, each project has a unique set of security requirements that, combined with door types, directions of travel, fire exit paths, and codes, makes for an infinite combination of lock types. There are several basic types of locks.

Electrified Strikes

Electrified strikes replace the conventional door strike into which a typical door latch closes. Unlike a conventional door strike, which requires that the door latch be retracted in order for it to open, the electric strike unlocks the door by simply folding back to release the door latch as the user pulls the door open. It springs back instantly as the door latch clears the strike so that it is ready to receive the latch as the door closes again. There are many types of electric strikes, but they all operate the same way. A few electric strikes are strong enough to be considered security devices, but most should not be relied on for high-security environments. Unfortunately, most electric strikes are not rated for their strength, which makes it difficult to determine whether one should rely on it to resist a forced attack. Any strike that does not list its physical strength should be assumed to be incapable of resisting a forced attack. One of the favorable attributes of electric strikes is that they do not draw power except when they unlock. This makes them suitable for environments in which power availability is a concern.

Electrified Mortise Locks

A mortise lock is a lock that is built into a routed pocked or “mortise” in the door. These locks are very strong because the lock is sizable relative to the latch and deadbolt and the lock is effectively part of the door, so it is essentially as strong as the door. When a mortise lock is placed in either a solid-core door or a hollow metal door, it is placed into a hollow metal frame. The result is a very strong door and lock. Mortise locks are available in a variety of configurations, the most common being office and storeroom types. The office lock is equipped with only a latch bolt, and the storeroom type is equipped with both a latch bolt and a deadbolt. Electrified mortise locks are simply normal mortise locks in which the latch bolt has been attached to a solenoid within the lock body so that upon triggering the solenoid the latch bolt retracts, unlocking the door. There are a few electrified storeroom mortise locks, but most are of the office type.

Magnetic Locks

Often considered the staple of electrified locks, the magnetic lock is little more than just an electromagnet attached to a door frame, and there is an armature attached to the door. When the electromagnet is energized and the armature on the door is against the lock, the lock engages. These are typically very strong locks, usually having 800-1500 lbs of holding force. This lock is sometimes stronger than the door to which it is attached. Magnetic locks should be used with a redundant means of unlocking to ensure that a person inside the locked area can always exit. A “Push to Exit” button or crash bar that interrupts power to the magnetic lock is always advised.

Electrified Panic Hardware

Where a door is located in the path of egress, panic hardware is often used, depending on the occupancy rating. Panic hardware is required on any door where there could be a large number of people needing exit in an emergency. Panic hardware is easily identified by the push bar (formerly called a crash bar) that the users press as they push through the door. Panic hardware facilitates a single exit motion because users have only to push on the door as they are moving through it. This facilitates the rapid exit of large numbers of people because no one has to wait behind anyone else while they stop to turn a door handle. In a severe emergency such as a fire, such momentary delays can compound to cause a crush of people behind a door that is unlocked but that can become a barrier if someone has difficulty with the door handle. There are several basic types of panic hardware configurations, depending on the requirements of the door to which the panic hardware is mounted. Panic hardware is electrified by one of several methods, usually involving a solenoid that releases a latch on the door.

Specialty Locks

Most people pay little attention to doors and locks; they just use them. However, there are a remarkable number of variations of doors, frames, locks, and electrification methods. Some unusual locks have been developed for special needs (see Chapter 7).

Switches

Door and gate position switches (DPS) sense if the door or gate is opened or closed. A variant of the DPS is the monitor strike, which determines if the door is not only closed but also whether a latchbolt or deadbolt is in fact engaged. The typical DPS is composed of a magnetically sensitive switch and a magnet placed close to the switch.

Typically, the switch is placed on the door frame and the magnet is placed on the door or gate. When the door or gate is opened, the switch also opens, sending a signal to the alarm system. Variants of DPSs include surface and concealed mounting versions (Figs. 6.13 and 6.14), wide- and narrow-gap sensing areas, and conventional or balanced bias types. Wide-gap DPSs were developed to prevent accidental triggering by nuisance conditions, such as when the wind blows against a sliding glass door.

To prevent an intruder from simply placing a magnet against the DPS while opening the door, balanced-bias switches were developed that place the switch in a closely controlled magnetic field. If another magnet is brought near the switch when the door is closed, that act alone will trigger an alarm even before the door is opened.

Other types of DPSs include plunger type, Hall effect, and mercury switches. These are sometimes used in areas where it is not possible to place a magnet in the door or gate or where a device must be alarmed if it is moved. The plunger switch alerts when the object that is pushed against it is moved. These are often mechanical switches and can be unreliable for high-security applications. Hall effect switches rely on the presence of a magnetic field within a confined area to alert. They also work by moving the object. Mercury switches are sometimes placed inside an object that should not be moved in any dimension and can be made to alert to the slightest movement. These are often used with radio frequency transmitters.

Duress Switches

Duress switches are usually placed under a desk or counter to alert security if the person at the counter feels threatened. The two most common types are finger activated and footswitch activated. If the person believes he or she needs assistance, he or she can either push a shrouded button (or two buttons together to prevent false alarms) or place a toe under and lift a footswitch. Another type used in cash drawer applications is the bill trap. This type activates when the last bill in a drawer is removed, indicating a robbery.

Request-to-Exit (REX) Sensors

It is good that a security system can alert when a door is opened, but what about a DPS at a door equipped with a card reader? When a person is exiting that door legally, there must be some way to sense that the exit is not an alarm and bypass the DPS for the duration of the door opening. This is what a REX sensor does.

There are two common types of REX sensors, infrared and push switch. An infrared REX sensor is placed above the door on the secure side and constantly monitors the door handle searching for human motion. When motion is sensed in the approach area to the door, the sensor activates and thus alerts the access control electronics that the pending door opening is a legal exit, not an alarm.

The push switch type is configured either as a labeled button near the door (required in most municipalities for magnetic locks) or can be a switch that is configured into the handle of a mortise lock or the electrified panic hardware push bar. These are more intuitive.

Even when other types of REX sensors are used on magnetically locked doors, it is still important to configure a labeled “Push to Unlock” button near the door. This button should be wired both to the access control system electronics to signal a legal exit and to the lock through a timer to ensure that if the access control system electronics should fail, the user may still exit the door. It is not only embarrassing but also can be legally costly and even deadly if a user is ever trapped inside a building with no way to exit.

Door and Gate Operators

Door and gate operators are mechanical devices that automatically open and close doors and gates in response to a command. Door operators are common in public buildings and assist in the movement of large numbers of people with little effort or assist handicapped persons through the door. Gate operators are commonly used to automatically open vehicle gates in response to a command.

Door operators are often used with magnetic locks such that the access control system may both unlock and then open a door. This is common at main public and commercial building doors, and this combination is also frequently used where there is a requirement to assist the handicapped. Wherever door operators are used with magnetic locks, it is imperative to sequence the operation such that the door unlocks first and then opens. If this sequencing is not built into the design, the automatic operator may fail after a short period of time. Better door operator companies have incorporated a special circuit for this purpose, but it must be specified. I designed one of the first such interfaces for a major door operator manufacturer. Doors that are in the path of egress must be equipped with safety devices to ensure that a person can exit in an emergency with no special knowledge. This typically means that there must be a labeled push button or some other type of code-approved method of egress. Codes will always prevail on any magnetically locked door. Do not assume that a code from one city is acceptable in another. Know your codes.

Gate operators that are electrically locked must also be interfaced in order to function correctly.

Revolving Doors and Electronic Turnstiles

Revolving doors and electronic turnstiles are sometimes used to provide positive access control. That is, each person must enter and leave using an access credential, and only one person may transit the portal at a time for accountability purposes.

Revolving doors (Fig. 6.15) can be equipped with a special operator that will allow only one person at a time through a rotating (X) pane. Like door operators, revolving doors can be locked between uses, but even when unlocked, they can be controlled by the operator so that only one rotation is permitted. Early revolving door operators were sometimes problematic. However, modern operators by major manufacturers are well developed, and most work well. It is wise to coordinate directly with the manufacturer of the revolving door operator to achieve the desired functions. These may include the following:

• Card reader controlled

• Remote bypass from a security console

• Auto-reverse if two or more people enter on one card use

• Auto-reverse if an unauthorized person attempts to use the door at the same time as an authorized user but from the opposite side of the revolving door

• Audio alert of improper use with instructions

Such doors are also available with status alerts on alarm, on reverse, with user count, and other options.

Revolving doors for access control should be configured to the “X” rather than “+” configuration when waiting for next use.

Electronic turnstiles (Fig. 6.16) are similar to the old-fashioned turnstiles used at subways and ballparks, except that the rotating member is replaced by an infrared photo beam that detects when someone passes through. There is also a type of electronic turnstile that uses paddle arms or glass wings to act as a physical barrier. These devices are designed to control access to a commercial or government building with a high degree of speed (throughput) and elegance. Electronic turnstiles must be used with an access control system that can deliver speedy card executions in order to be accepted by the users. As for revolving doors, the designer should coordinate the specifications carefully with the turnstile manufacturer.

Electronic Processing Components

Electronic processing components include reader interface boards, alarm input boards, output relay boards, and controllers. Every alarm and access control system made today uses some form of controller between the workstations/servers and the field devices (Fig. 6.17). These vary slightly from manufacturer to manufacturer, but the theme is the same. Each has three basic elements:

• A microprocessor with connectivity to the server and other controllers

• Memory

• Field device interface modules (reader interface boards, alarm input boards, and output relay boards)

The configuration may vary (some systems combine these elements together into one board, whereas in others they are components that can be distributed or wired together in one electrical box), but all systems use these same elements. However, that will change soon.

When I began writing this book in 2006, the concept of microcontrollers, which I had long proposed, was scoffed at by most in the industry. However, by the time this book was published in its first edition, at least one manufacturer was making small microcontrollers that control a single door, with some auxiliary inputs and outputs. At that time I said that newer generations of microcontrollers will contain their own memory and microprocessor. They will fit in a small box above the door. All that has come to pass. I also said that they will eventually incorporate a mini data switch connected by Ethernet. So far that has not happened, although I understand it to be under discussion as the second edition of this book goes to press.

I said then that this design would revolutionize the industry. The alarm and access control industry has been based for years on metal bending—that is, on the sale of hardware. This is about to become a software industry. It is part of the sea change mentioned previously.

Soon, it will be possible to connect a card reader, DPS, REX, and lock, together with an intercom outstation and a video camera, into a single small electronic smart switch that will contain its own central processing unit and memory. I have been predicting this for more than a decade, and now as the second edition goes to press, it is occurring.

Data Infrastructure Basics

When the user presents a card to a card reader and the card reader passes that information to a controller, a decision is made to unlock the door. That information, along with alarm detection information, is transmitted along a data infrastructure to the server, and then it is distributed to appropriate workstations. The data infrastructure is the backbone of the system. In older systems, there was a unique data infrastructure for the alarm and access control system, but most modern systems have converted to an Ethernet communications protocol. Older protocols included RS-485, Protocol A, Protocol B, 20-ma current loop, and other methods. The newer Ethernet protocol supports worldwide systems architectures that can be connected in many different ways to meet the special needs of each client, each site, and each security environment. Additionally, Ethernet protocols can also communicate CCTV and voice technologies all on a single data infrastructure. Ethernet can be easily converted to fiber optics, 802.11a/b/g/n, laser, or geostationary satellite and even on SCADA systems to facilitate unique environmental requirements where normal wired infrastructures present design challenges. It would be easy to write an entire book(s) on the subject of security system data infrastructures, and it is a difficult subject to boil down to its basics. More information on this subject is presented here and in the System Commissioning section of this book.

Interfaces to Other Building Systems

Alarm and access control systems begin to perform wonders when they are interfaced to other building systems. Typical interfaces include fire alarm systems, elevators, parking control systems, lighting control systems, signage, roll-down doors, private automatic branch exchange (PABX) systems, paging systems, water features, irrigation control systems, and even escalators. The primary purposes for interfacing alarm and access control systems to other building systems is to control access to things other than doors and gates, enhance safety or convenience to building users, automate building functions that would otherwise be handled manually or by numerous other systems, or insert a delay into the path of an intruder.

One of the key challenges facing enterprise security systems designers is how to integrate the new technology into older, legacy systems. Typically, government entities and large corporations have developed their security systems in a somewhat haphazard fashion. This resulted from the fact that electronic security was initially addressed at the local level in almost all large organizations, and only later did they come to realize that there was a value to having a single standard across the entire organization. The result was that most organizations had many different types of products across various sites that were difficult to blend into a single contiguous system. To complicate this problem, the security industry has a long tradition of proprietary systems that are not based on any single standard (with the exception of CCTV systems, which had to conform to the preexisting NTSC standard). Virtually every alarm and access control system and every major security intercom system used components that could not be interchanged.

This problem was compounded by the early introduction of digital video systems that were based on proprietary compression technologies, which again ensured that the stored data could not be shared with their competitors’ products. The first piece of good news is that the entire suite of enterprise security system components connects to Ethernet data infrastructures.

The bad news is that there are three not entirely small problems:

• Older and current alarm and access control systems still use proprietary software interfaces that in most cases are not intended to link their data with other competing systems. Manufacturers still seem to hope against all logic that their clients will gleefully abandon all installations made by other manufacturers and replace them with equipment made by them.

• Different digital CCTV manufacturers have adopted varying video compression technologies, making interfacing to a single standard difficult. Some manufacturers have even modified existing compression algorithms to become proprietary to them alone.

• As security intercom manufacturers move to digital products, they are also adopting numerous different compression protocols, again making a single platform more difficult.

Now the second piece of good news: Computers are very good at operating multiple protocols together on the same platform. That means that unless the compression protocol is truly unique, it is possible to combine multiple protocols into a single operational platform.

The third piece of good news is that some of the alarm and access control system manufacturers are beginning to make uniform interfaces to create multi-system interoperability.

The fourth piece of good news is that, in almost all cases, it is not necessary to fully interface different systems together in order to get them to cooperate in truly meaningful ways. Interfacing methods are discussed in detail in Chapter 14.

Data versus Hardware Interfaces

Alarm and access control systems are often interfaced to other building systems, such as elevators and building automation systems. There are two ways to accomplish these interfaces. They can be realized either by exchanging data information or by handshaking with dry contacts between the two systems. There are advantages and disadvantages to both approaches.

Data interfaces have wonderful advantages. First, a single data interface (one little wire) can last a lifetime, no matter how many times the systems are expanded, adapted, and upgraded. Once the original data interface is connected and the software is interfaced, the systems can be adapted repeatedly to expand the quantity and functions of the interfaces.

Second, that single wire can control an empire. Once an interface is conducted on a network, it is global. It is not necessary to interface each and every site if the systems can communicate by a data interface.

Although data interfaces are wonderful, because they rely on software, they are vulnerable to software upgrades. When software is upgraded, it is not uncommon for software programmers to forget the little details of the last issue that almost nobody used. Nobody used it; it cannot be important enough to keep updated while we are under a tight schedule to meet the upgrade release date. We can pick that up in a patch later. Thus, the poor unsuspecting client eagerly awaiting his or her new software upgrade installs it and the interface does not work any more—instant software data interface vulnerability. There are indeed organizations that have had to reinstall obsolete software in order to maintain an old data interface.

Likewise, there are advantages and disadvantages to hardware interfaces. Hardware interfaces are accomplished by connecting the dry contact of a relay in one system to the input point of another system. This allows the first system to signal the second system that some condition has changed and the second system should do something about it. This simple principle is multiplied to accommodate as many individual connections as each system needs. Relays can be combined to perform logic (and, or, not, and if), and they are reliable. Once a relay interface is set up and tested, it does not matter how many times the software is updated on either system. It will always work.

The disadvantage of hardware interfaces is that they are generally site specific and they are entirely inflexible. If the system is expanded, and more interface points are needed, more relays and more inputs will be required—more expense every time there is a change or expansion. Thus, it is a trade-off. Each system requires an individual decision as to what is in the best interest of the organization.

Analog video is created in a video camera by scanning an electron beam across a phosphor. The beam intensity is determined by the amount of light on each small area of the phosphor, which itself responds to the light being focused on it by a lens. That beam is then transmitted to a recording, switching, or display device. Analog switchers simply make a connection between devices by closing a relay dry contact. Recorders simply record the voltage changes of the electron beam onto tape, and display devices convert the voltage back into an electron beam and aim it at another phosphorus surface, which is the display monitor that is viewed.

Capturing and Displaying Digital Video

Digital video images are captured entirely differently. Light is focused by a lens onto a digital imager. This is an integrated circuit in which the “chip” is exposed rather than covered by the plastic body of the chip, as in a normal integrated circuit. It is a little known fact that virtually all integrated circuits respond to light. Early electronic programmable read-only memory chips were in fact erased of their programming by “flashing” them with light. This phenomenon was utilized to make an integrated circuit that comprised hundreds of thousands (today millions) of individual light-sensitive chips. When light was focused on this chip, it responded by creating a different voltage in each individual picture element (pixel) in direct proportion to the amount of light striking that particular element. A matrix was formed from the output voltages of each row and column of chips, and this lattice was then scanned to replicate the voltage of a conventional tube-type video imager. The result was the world’s first digital imager. Video can be displayed in much the same way as it is gathered. The most common technologies today are liquid crystal displays (LCD) and plasma displays for directly viewed displays and digital light processor (DLP) devices for projected video. All of these are variations of the same basic concept. A semitransparent color pixel (blue, green, red) is arrayed in front of an illuminator. The video image is fed to the display and the pixels do their job, displaying the video images. LCD displays have become the de facto standard for smaller displays, and plasma and LCD displays are both common for large screens. DLP projectors accommodate most displays over 60 in. diagonal, except for video walls, which are composed by grouping arrays of LCD, plasma, or projected video box displays.

Archiving Analog and Digital Video

Analog video is transmitted as a fluctuating voltage with codes embedded for color, hue, and gamma. This fluctuating voltage is processed and fed to a recording head. The basic analog recording head for video works on the same principle as an analog audiotape recorder; that is, a current is fed to a specially formed electromagnet, which is formed to present a smooth surface to the tape that is being swept across the head by a pair of rotating reels. The electromagnet has a very tiny gap, across which a magnetic flux is developed in response to the fluctuating current. As the tape is rolled across the tiny gap in the recording head, the tape is magnetized in direct proportion to the current in the electromagnetic head. To play the tape back, the same tape is moved past another playback head, and the magnetic signals recorded on the tape are converted back to electrical currents, corresponding to the originally recorded signal. Videotape differs from audiotape in that the heads are slightly tilted and spun in order to record a series of diagonal stripes, each corresponding to a field of a video frame (Fig. 6.18). There are two fields for each video frame, and these are interlaced such that the first field records or displays 525 stripes of video. The beam is then shifted down to an area between the first and second stripes of the first field, and then the process is repeated for the second field of 525 stripes. When both fields are displayed together, the result is that the two fields are combined together to form a single video frame. Two fields are used because by painting the entire screen twice, and by shifting the second field slightly down from the first field so that its lines lie in between the lines on the first field, the image is of higher resolution than that of just one field and they are interlaced so that the eye does not catch the time difference from the first stripe at the top of the screen to the last stripe at the bottom.

Digital video is transmitted instead by a string of data packets. Each packet is composed of ones and zeros in a designated format. The packet has a header, footer, data, and, sometimes, encryption.⁵ The header has the packet address (where it comes from and where it is going, what kind of data are in the packet, how much data are in the packet, the camera identifier, date and time, and other information). The footer has information that closes the packet so that the destination device knows it has received the whole packet. Each packet of video is stored on digital disk or digital tape, and the video can be retrieved based on its time code, camera number, the alarm condition that the video is recording, or any other criteria that may have been stored in the header.

Digital Transmission Systems

Digital video packets are transmitted in either of two basic protocols: Transport Control Protocol (TCP) or User Datagram Protocol (UDP)/RDP. TCP (Transport Control Protocol) is a one-to-one communication relationship—one sending device and one receiving device. Well, that is not entirely true. TCP packets can in fact be broadcast to many destination addresses, but it requires opening an individual one-to-one session for each destination device. Where many cameras and several monitoring stations are involved, this can consume so much of the network’s resources that the entire system can freeze from data overload. For these situations, the network designer selects UDP or RDP protocols.

Wireless Approaches and Frequencies

There are usually many ways to do things, and that is certainly true for wireless video. Following is a list of the most common ways of transmitting video wirelessly:

• Laser: Although becoming more difficult to find, laser transmitters and receivers have several advantages over other methods. The system typically comprises a laser transmitter and receiver pair, with optical lenses and weatherproof enclosures. The system is normally one-directional, so it is not well suited for pan/tilt/zoom cameras that need control signals. Laser video transmitters are immune to radio frequency noise but are affected by heavy fog or rain or blowing objects (Fig. 6.19).

• Microwave: Microwave wireless systems can transmit either analog signals or data. Unlike laser and many radio systems, virtually all microwave systems require a license. Properly applied microwave systems can transport signals considerable distances, typically up to 20 miles. Microwave systems can be bidirectional and require careful, permanent placement. Although temporary systems exist, those are usually deployed by the military, not for civilian use. Microwave systems are subject to a variety of interference factors, including fog, rain, lightning, and other microwave signals. However, when fiber is not practical and radio frequencies are a potential problem due to other radio frequency interference, microwave is often a sure thing (Fig. 6.20).

• Radio: Most wireless video today is transmitted over radio waves. These can be either analog or digital. Radio-based wireless systems are of two types, licensed and unlicensed. It is often more reliable to use licensed systems for permanent installations because interference is less likely.

• Frequencies: The following are common frequencies for radio video transmitters/receivers:

440 MHz (FM TV–analog)

900 MHz (FM TV–analog and digital)

1.2 GHz (FM TV–analog)

2.4 GHz (FM TV–analog and 802.11 digital)

4.9 GHz (public safety band)

5.0-5.8 GHz (802.11 digital)

10-24 GHz (digital)

Analog

There are very few analog transmitters and receivers available today. Most of them are in the UHF frequency band. Analog transmitter/receiver pairs suffer from radio frequency noise and environmental conditions more so than do digital systems, and their signal becomes weaker with distance, affecting their image quality. Analog radio systems directly transmit the analog PAL/NTSC video signal over the air. Most of these systems require a license if their power is more than 50 MW.

NTSC is a transmission standard named after the National Television Standards Committee, which approved it for use in the United States. It transmits a scan rate of 525 at 60 Hz and uses a video bandwidth of 4.2 MHz and an audio carrier of 4.5 MHz.

PAL stands for phase-alternating line. PAL is used in many countries throughout Europe, Africa, the Middle East, South and Southeast Asia, and Asia. PAL signals scan 625 lines at 50 Hz. The video bandwidth is 5.0 MHz and the audio carrier is 5.5 MHz. Some countries use a modified PAL standard called PAL N or PAL M. PAL N has a video bandwidth of 4.2 MHz and audio carrier of 4.5 MHz. PAL M has a scan rate of 525 lines at 50 Hz, video bandwidth of 4.2 MHz, and audio carrier of 4.5 MHz.

Analog frequencies were shown previously as FM TV (see the list above).

Digital

Digital radio frequency systems transmit IP (TCP/IP or UDP/IP) signals over the air. Typically, to transmit video, either the video signal is sourced directly from an IP-enabled video camera, or an analog video signal (PAL/NTSC format) is converted to UDP/IP through a video codec.

Video Analytics

Video analytics is a technology that processes a digital video signal using a special algorithm in order to perform a security related function. There are three common types of video analytics:

- Fixed algorithm analytics

- Artificial intelligence learning algorithms

- Facial recognition systems

The first two of these both try to achieve the same result. That is, they try to determine if an unwanted or suspicious behavior is occurring in the field of view of a video camera and the algorithm notifies the console operator of the finding. However, each takes a dramatically different route to get to its result.

Fixed algorithm analytics use an algorithm that is designed to perform a specific task and look for a specific behavior. For example, common behaviors that fixed algorithm analytics look for include:

- Crossing a line

- Moving in the wrong direction down a corridor

- Leaving an article

- Picking up an article

- Loitering

- Floating face down in a swimming pool

Each fixed algorithm looks for a very specific behavior. The client must pay for each individual algorithm for each individual video camera in most cases.

Artificial intelligence learning algorithms operate entirely differently. Learning algorithm systems begin as a blank slate. They arrive completely dumb. After connecting to a given camera for several weeks, they begin to issue alerts and alarms. During that time period the system is learning what is normal for that camera’s image during the day, night, weekday, weekend, and hour by hour. After several weeks, the system begins to issue alerts and alarms on behavior in the screen that it has not seen before or that is not consistent with what it has seen during that time period for that day of week.

An example illustrates the usefulness of this approach. In one early installation at a major international airport that was intended to spot children climbing on a baggage carousel, the system alerted on a man who picked up a small bag from the carousel and placed it inside an empty larger bag. The man was intercepted and interrogated only to discover that the luggage inside his did not belong to him and that he was part of a ring that came to the airport regularly to steal baggage in this way. The airport had no idea this was even occurring, so there was no way they could have purchased a fixed behavior algorithm for this, even if such existed (which it did not). This approach to video analytics is most useful.

The third type of analytic is facial recognition. Facial recognition systems can be used for access control or to help identify friend or foe. Facial recognition systems can also be used to further an investigation.

Typical facial recognition systems match points on a face with a sample stored in a database. If the face does not match a record, it will try to create a new record from the best image available of that person. These are capable of making real-time matches of one image against many. The latest version of facial recognition systems constructs 3D maps of faces in real-time and compares those to a truly vast database. One manufacturer claims to be able to match individuals in real-time against a country-sized database of images (millions of records).

Traditional facial recognition systems require well-lit scenes and fairly static backgrounds. The latest versions are reported to work under fair to poor lighting and with dynamic backgrounds.

Lenses and Lighting

Lenses are to video what loudspeakers are to audio systems. Just as there is a dramatic difference in the quality of audio depending on the quality of the loudspeaker playing the music, so also the quality of lenses directly determines the quality of the video image. For many years, security installers used to place cheap plastic lenses on otherwise good video cameras in order to present a price advantage against their competition. The result was very poor and sometimes virtually useless video images. With the introduction of mega-pixel video cameras as expectations of better quality images increased, many users were very disappointed to see poor images from very expensive cameras when the installers fitted them with standard quality lenses.

It is very important to use only good lenses on every video camera. And it is especially important to use only mega-pixel quality lenses on mega-pixel video cameras. A good lens will be all glass, coated to reduce flare and should be an achromatic design, which brings red and blue to focus at the same point on the focal plane. Manufacturers of cheap plastic lenses often use euphemisms to conceal their poor construction, calling them something such as “optical resin.”

Lenses should be back-focused in the camera to assure that its focus is exactly fitted to the camera. The designer should pay attention to be sure that this has been done and quiz the installer on how it is done so that one can be certain the required skills are present in the installer.

Likewise good lighting is essential for a good quality image. Good lighting has three main components: lighting level, lighting contrast, and lighting color temperature.

Two-Way Radios

Two-way radios are the heart of communications for any security staff. They provide the ability for security officers to communicate with each other and with other facility personnel, including management and maintenance/cleaning staff. Two-way radios are used for communications from the security console to field officers and from officer to officer in the field.

Two-way radios have varying frequencies. Common spectrum sections include the 150- and 450-MHz bands. Radios with 800 MHz are a blend of traditional two-way radio technology and computer-controlled transmitters. The system’s main advantage is that radio transmitters can be shared among various departments or users with the aid of computer programming. Virtual radio groups, called “talk groups,” are created in software to enable private departmental conversations. This gives the system the look and feel of one having many different “frequencies” when in fact everyone is sharing just a few. A quick reference of public and private radio frequencies can be found at http://www.bearcat1.com/freer.htm.

Cell Phones

Cell phones can provide an inexpensive means of communications, particularly cell phones with a two-way radio function. They provide in a single unit both a two-way radio and the ability to call the police directly when needed, as well as managers.

Cell phones have limits, however. Before deciding on using a cell phone as a primary means of communication, it is important to conduct a test with the type of cell phone planned for use in every dark recess of the building, parking structure, stairwell, restroom, storage room, and throughout the entire facility. Otherwise, you may discover a dead spot in exactly the place where the worst possible emergency is occurring, exactly when it occurs.

Cell phones are particularly valuable for patrol officers in vehicles because of their wide geographical reach, allowing the officer to be reached both on and off the property.

Intercoms

Security intercoms enable console officers to talk to anyone near a field intercom station (typically another officer or a member of the public). Calls can usually be initiated either from the console or from the intercom field station by pressing a “call” button. Most intercoms are hands-free devices, although handsets are sometimes used. ADA (Americans with Disability Act)-compliant intercoms also provide a visual indicator that the call has been sent and acknowledged, in case the user is hearing impaired.

Other types of intercoms include call-out only stations and intercom bullhorns. Call-out stations are similar to standard intercoms but are not equipped with call buttons. The console officer always originates the call for this type. Intercom bullhorns are similar to call-out stations but are equipped with a horn that acoustically amplifies the audio so that the console officer and subject can communicate at farther distances (usually up to 100 ft). Intercom bullhorns usually also require an auxiliary amplifier in order to provide adequate power to be heard at that distance. The horn gathers the voice of the subject, although it is more difficult for the officer to hear the subject than it is for the subject to hear the officer. Bullhorns are often used only for directions to the subject and not back to the officer.

Emergency Phones

Emergency phones (also called assistance phones) are intercoms that are also equipped with flashing lights or strobes to help a responding officer find the subject who is calling and to deter a crime against that subject because the strobe calls attention to the area, making a crime of violence less probable.

Paging Systems

Paging systems are strictly for communication from the console officer to the field. Paging systems can be specific to a single paging speaker or horn or to a field of speakers and horns in order to cover a large area. Paging systems are useful for making announcements to large numbers of people simultaneously, such as to order an evacuation or to issue directions in an emergency.

Intercom and voice systems historically used analog communications—that is, a microphone was connected to an amplifier and a speaker. For larger systems, a matrix switcher was used to manage one or a few console communications paths out to many field intercoms. This is called a circuit-switched network. Traditional telephone systems are also circuit-switched networks. Each circuit can carry only one communication and there must be a continuous wire connection from speaker to subject. This approach is fine for a single site, but it has drawbacks, including the fact that the wiring is of a fixed architecture, so one intercom master station wires to many field stations. If one wants to add more master stations, one must wire from master to master. There is a single point of failure at the main master where the field intercom stations are first wired. Also, when the organization wants to move the location of the main master station, much costly rewiring is necessary.

Digital

For enterprise systems, the drawbacks of circuit-switched networks present major problems. How do you maintain a circuit from New York to California? The cost of leased lines is too high, so digital intercoms are used. As digital video systems become more prevalent, it is also easier to “piggyback” voice communications on that digital path. Digital systems use packet-switched networks instead of circuit-switched networks for communications. Therefore, their path can be dynamic. If the organization wants to move its console, it only has to connect the new console to the nearest digital switch.

Digital intercoms have certain drawbacks too. For security, audio is more important than any other communication. Dropped audio could mean a lost life. So audio communications must be configured as the priority communication in order to ensure that no communication is lost as, for example, a new screen of video cameras is loading from one guard tour to the next. This is a programming element and cannot be configured in software if it is not written into the code. Audio compression protocols commonly include the G.7xx series, including G.711, G.721, G.722, G.726, G.728, and G.729. Another common protocol is the MPEG protocol, including MP-3. These are all UDP protocols. The software designer must ensure that the audio protocol is given priority of communications over the digital and data protocols. Where this is not done, the security officer can find it difficult to talk while video is loading. This condition is unacceptable, although at the time of this writing several video software manufacturers publish software with this flaw. Their common workaround is to require an additional client workstation just for audio. This is one of those design flaws that no one would buy if he or she knew about it ahead of time.

Digital audio has many advantages. Additional intercom stations can be added on anywhere an extra switch port exists, dramatically reducing wired infrastructure costs. Additional switches can be added at little cost in new infrastructure. For enterprise systems, the Internet or asynchronous transfer mode networks permit communications across state and national boundaries, making possible a monitoring center in one state that monitors sites throughout the world.

Wireless Digital

Any digital communication can be configured to operate wirelessly as well as on a wired network. This enables communications to remotely located emergency phones across an endless expanse of park or parking lot. All one needs is power, and that can sometimes be obtained via solar panels and batteries. Emergency phones are an ideal application for solar panels and batteries because they draw power only when in use, except for a small amount of power for the radio frequency node. This is usually very low, typically less than 25 W for a well-designed system.

Communication System Integration

It is also possible to integrate two-way radios, cell phones, land phones, and intercoms into a consolidated communications system (CCS). Typically, there are only one or two security officers at a console, but there may be many communications systems. In the worst case I have seen, at a high-rise building in Los Angeles, there were 10 separate intercoms for elevators, 4 intercom systems for security, 4 two-way radio systems, 2 paging systems, 8 telephone lines, and cell phones. All this was (barely) manageable until an earthquake struck. Then, chaos broke loose in the security console room. Remember, that was 29 separate communications systems for a console room with one or two officers. That does not work very well.

In an ideal configuration, the systems have been coordinated such that there is no more than one of each type of system (interdiscipline coordination-instilled design flaws) and those few systems are further coordinated into a “CCS”. The CCS assembles the various communications platforms into a single piece of software that manages the communications to a single (or multiple) console officer station. Calls that cannot be taken are queued.

Queued calls go to an automated attendant that provides feedback to waiting parties. In the earthquake example, people in a stopped elevator would hear an automated message from the intercom speaker when they press the help button advising them that an earthquake has just struck the building and that there is a heavy demand on the security console officer and advising them that their call is in a queue. They would be advised to push the help button a second time if there is a medical emergency, advancing their call in the queue. In the meantime, there would be a digitized ring tone and recorded message with enough variation to keep their anxiety level low. The system could also advise them of the expected wait time.

Consoles and workstations provide a means to instruct the security system on how to behave and interact with its environment and users, to provide a face for the security system to its human user (viewing cameras, using the intercom, responding to alarms, etc.), and to obtain system reports. There are a limited number of common implementations of these types of workstations. System size dictates the type.

Vetting Alarms

Any alarm that occurs anywhere in the security system will report to the guard console. The console software should be integrated to extend its eyes, ears, and mouth into the depths of the facility, wherever an alarm occurs. The guard should receive immediate notification of the alarm and immediately be able to verify the alarm from the console. Often, the best way to do this is by the presence of a video camera near the alarm. If the alarm is verified as an intrusion, the console guard must then take some action, either dispatching an officer to respond (radio) or confronting the subject via security intercom. For this reason, good design principles indicate that, where possible, every alarm should have a camera nearby to permit alarm verification. Ideally, there should also be a field intercom station or field talk station near the camera to direct the subject away from the area of the intrusion. Additionally, the software should be configured such that for every alarm a camera is programmed to queue for display automatically, and that camera image should be recorded. For digital video systems, a pre-event record period is also recommended. That is, even if the camera is not programmed for continuous archiving, the system should be archiving every camera continuously for 2 minutes such that in the event of an alarm for which that camera may respond, that 2 minutes being recorded before the alarm becomes part of the alarm video event archive. Otherwise, it is recorded over continuously.

Granting Access Remotely

Another common function of guard consoles is the remote granting of access to authorized visitors, contractors, and vendors. Typically, one or more remote doors may facilitate such access. If there is a constant flow of people through the door, it may be appropriate to locate a guard there to facilitate authorization and access granting. However, often the flow does not warrant the cost of a full-time guard. For such cases, it is ideal if there can be configured a vestibule for access granting to include a card reader for authorized users, a camera, and an intercom to facilitate a gracious granting of access privileges. These designs take two common forms.

Video Surveillance

Video surveillance involves the act of observing a scene or scenes and looking for specific behaviors that are improper or that may indicate the emergence or existence of improper behavior.

Common uses of video surveillance include observing the public at the entry to sports events, public transportation (train platforms, airports, etc.), and around the perimeter of secure facilities, especially those that are directly bounded by community spaces.

The video surveillance process includes the identification of areas of concern and the identification of specific cameras or groups of cameras that may be able to view those areas. If it is possible to identify schedules when security trends have occurred or may be likely to occur, that is also helpful to the process. Then, by viewing the selected images at appropriate times, it is possible to determine if improper activity is occurring.

One such application is for train platforms. Following a series of reports of intimidating behavior at a particular train platform, the use of video cameras and intercoms was found to reduce the potential for such events as the perpetrators began to understand that their behavior could be recorded and used to identify them to police. Furthermore, the act of getting on a train did not deter the police who boarded at the next station and apprehended the criminals. Word got around and the behavior was reduced dramatically.

Video Guard Tours

The use of correlated groups of video cameras programmed to be viewed as a group allows the console officer to see an entire area at once. He can then step through the spaces of the facility, each time viewing the entire area as though he were walking through a guard tour.

It is much faster to perform a virtual video guard tour than a physical guard tour, thus allowing more frequent reviews of the spaces. Additionally, because the cameras are always in place, people behaving improperly are unaware that they are being viewed by authorities until a response occurs, either by dispatched officer or by intercom intervention, either of which can be effective in deterring improper behavior.

Video guard tours are especially effective at managing very large facilities, such as public transportation facilities in which the spaces can be vast and the time to travel between areas can be significant.

Video Pursuit

The guard tour cameras can also be set up to create a “video pursuit” that will allow a console officer in an environment such as an airport or casino to follow a subject as he or she walks through the space by selecting the camera in the group into which the subject has walked. With each selection, a new group will be displayed where the new display includes the selected camera and other cameras displaying views into which the subject might walk if he or she leaves the area under display. As the subject moves from camera to camera, video pursuit keeps the subject centered in a cocoon of cameras. A corresponding display of maps will show the console officer where the subject is located by highlighting the central camera and those around it where the subject might walk.¹²

Security System Intercoms

Security intercoms provide a convenient way for visitors to gain information or access at remote doors. They may be used either to facilitate remote access granting or to direct the visitor to a visitor lobby. The visitor can query the console security officer by pressing a call button on the intercom, thus initiating a call. Likewise, the console security officer can also initiate a call directly from the console.

A second type of intercom is the officer-controlled security intercom. Similar to a conventional intercom station but without the call button, these are often placed next to a video camera for use in directing a subject after verifying an alarm.

The third type of security intercom is the intercom bullhorn. It is similar to the officer-controlled intercom, but has the ability to reach farther distances due to the bullhorn.

Elevator and Parking System Intercoms

Security intercoms are often located in elevators and elevator lobbies and at parking entrances.

Emergency Call Stations

A security intercom coupled with a blue strobe and emergency signage, this intercom is a welcome point of help in areas where an assault could occur, such as in parking structures and walkways on a college campus. Reports indicate that assault crimes can diminish from historical norms where emergency call stations are used.

Digital intercom systems utilize a codec from the field intercom station to the digital infrastructure. The digital video software often accommodates the communications path and can also automatically queue the intercom for use whenever the camera viewing the intercom is on screen. That can be accomplished automatically in response to an alarm.

Analog intercoms use either two-wire or four-wire field intercom stations. Four-wire intercom stations use two wires for the speaker, two for the microphone, and sometimes two for the call button, whereas two-wire intercoms use only two wires for all three functions. Four-wire intercoms can operate in full-duplex mode (simultaneous talk/listen), whereas two-wire intercoms can only operate in half-duplex mode, although this is often more advisable because it allows the console security officer to control the conversation and ensures that conversations in the console room will not be unintentionally overheard at the field intercom station.

Direct Ring-Down Intercoms

These are telephones that ring to a specific number when the receiver is lifted or the call button is pressed (hands-free version). These are commonly used in elevators and emergency call stations. Direct ring-down phones are available in both CO (central office line connection) and non-CO versions (non-CO versions create their own ring-down voltage and need only a pair of wires connected to an answering phone station set). These are frequently used for remote parking gates. Both types are also usually equipped with remote control over a dry contact relay at the ring-down station, permitting remote access through a parking gate or door.

Two-Way Radio

Two-way radio systems facilitate constant communications among a dispatcher, console security officer, security management, security guards, and building maintenance personnel.

Two-way radio systems can comprise an assembly of handheld radios with no master station or may be equipped with a master station at the security command center. In any event, a charging station will need to be accommodated in the space planning of the security command center.

Two-way radio systems can be integrated via communications software with other communications systems to create a CCS that can integrate radio, telephone, pagers, and intercoms into a single communications platform.

Pagers

Pagers can be used to notify roving security officers of an alarm or can discretely notify an officer of a condition requiring his or her attention. Many alarm/access control systems can connect directly to a paging system transmitter for local broadcast within a building or on a campus. The systems can also be connected to a telephone dialer in order to broadcast a page across a city or the country. At a minimum, the security console can be configured to utilize paging software to key in messages independent of any other interface.

Wireless Headsets

For security consoles and lobby security desks that require the console officer to move about considerably, it is useful to equip the intercom/telephone or two-way radio with wireless headphones. These free the console officer from the common tether of a standard headset.

Wireless headsets can be connected a variety of ways depending on the manufacturer and model, including to a headphone plug, USB, or RS-232.