Home > Articles

This chapter is from the book

This chapter is from the book

Physical Devices

The six major physical components of a home security and surveillance system are described in this section. Although some designs include additional components for enhanced performance or custom installations, the physical devices described here are considered the basic building blocks for a security and surveillance system that will provide adequate protection from intrusion. The essential physical assemblies include

  • Keypads

  • Sensors

  • Security panels

  • Cameras

  • Monitors

  • Switchers

Keypads

The keypad is the device used by the home residents to initiate commands for control options and observe the status of the security system. As shown in Figure 3.3, it usually contains an alphanumeric keypad and LED displays that indicate the status of the alarm system.

Figure 3.3Figure 3.3 Keypad.

The keypad is used to arm and disarm the system and often includes a panic switch by which the alarm can be triggered instantly in an emergency situation. The alarm can be silenced by the owner by entering the correct coded sequence of numbers on the numerical keypad. The keypad is typically installed inside the home near a door that is most frequently used by the residents. A programmed delay is included as a feature of most systems to enable the users to enter and disarm the system within a fixed delay period (normally 30–45 seconds). The same fixed delay is also used to allow the user to arm the system and exit the home within the fixed delay period. Keypads can also be used to bypass certain areas.

NOTE

The bypass function is used to arm the system but disable selected zones or motion detectors inside the home when the family is present. Residents often desire to secure the perimeter area of doors and windows after retiring for the evening but need to bypass interior area motion detection sensors that are activated only when the home is not occupied.

Sensors

Sensors are designed to protect both the perimeter and the open spaces inside the home. As mentioned earlier, perimeter devices primarily protect doors and windows. The most common perimeter sensors are magnetic door switches, window vibration detectors, and window acoustical detectors. Space protection sensors called motion detectors cover interior rooms and hallways and can detect an intruder who has been able to defeat a perimeter device. Exterior motion detectors and motion-activated security lights are also used. The following paragraphs describe the types of sensors required in basic home security and surveillance systems.

Door Switches

Door switches work on a basic principle of a two-part magnetic switch. A switch that is sensitive to a magnetic field is mounted on the fixed structure (frame), and wires from the switch are routed through the wall to the control panel. A magnet is mounted on the door in a position where it is in close proximity to the switch when the door is closed; this also keeps the switch closed. Opening the door moves the magnet away from the switch and causes the switch to "open," which is sensed by the central control panel and activates an alarm. Magnetic switches are available as normally open (NO) or normally closed (NC) to accommodate different wiring designs and controller options.

Window Acoustic and Vibration Detectors

As you learned earlier, window sensors are used to detect the sound of breaking glass. Large glass doors such as patio doors are usually protected by magnetic switches. Windows in the home can also be protected by magnetic switches if they can be opened; however, glass break detectors are recommended by most home security contractors to protect against an intruder entering through a broken window.

Glass break detectors are available in either vibration type or acoustical type. The vibration type is mounted on the glass or on a nearby wall.

CAUTION

Security system magnetic switches are designed for both normally closed (NC) and normally open (NO) options. An NC switch opens when the magnet is moved near the switch, and an NO switch closes when the magnet is moved in close proximity to the switch. This enables magnetic sensor-type switches to be used with various types of security system designs. Sensor door switches wired in parallel use NO contacts so that any closure of the contacts in the circuit activate an alarm condition. Series circuits use NC magnetic switches where any opening of a switch results in an open condition for the circuit, which triggers an alarm condition by the controller.

Motion Detectors

Motion detectors work by detecting the changes in the infrared energy in an area. Because these devices do not emit any energy, they are called passive infrared (PIR) detectors. PIR detectors use a lens mechanism in the sensor housing to detect a change in infrared energy across the horizontal sectors covered by the sensor. This type of detector is insensitive to stationary objects but reacts to rapid changes that occur laterally across the field of view. They are the most common and economical type of motion detectors and are available in standard, pet-friendly, and harsh-environment (outdoor) models. An example of a motion detector for interior use is shown in Figure 3.4.

Figure 3.4Figure 3.4 Motion detector.

Security Panels

Security panels provide several functions to coordinate the operation and management of a security system. They can include an integrated keypad or LED indicators. Most designs include a power transformer for converting the AC voltage to a DC voltage for the sensor loop and contain a rechargeable battery for backup if the commercial power fails. A terminal strip provides for the connection of the wiring that connects all the sensors to the controller as well as the external telephone line. Most designs include a printed circuit board containing all the electronics and a microprocessor. It also connects to and controls the siren that is activated when an alarm condition exists.

Security panels are known by numerous names, such as central control box, control panel, alarm panel, and interface panel. They all perform similar functions including controlling and monitoring sensor status, providing power to the system, connecting the telephone line to the monitoring station, and handling the programmable options for the system.

Cameras

Surveillance systems for the home use video cameras that convert the image into a video composite or S-video signal for display on a video monitor. The best type of camera for home systems uses charged coupled device (CCD) technology. These cameras have high resolutions, low operating light, less temperature dependence, and high reliability. A typical CCD camera used in video surveillance systems is illustrated in Figure 3.5.

Figure 3.5Figure 3.5 Video surveillance camera.

Camera Resolution and Sensitivity

The two important specifications for cameras are the light sensitivity rating and the number of lines of resolution. The resolution of a camera is a measurement of the horizontal lines it is capable of generating. Most standard TVs and VCRs have a resolution of fewer than 300 lines, but video monitors can have a resolution as high as 800 lines. Surveillance cameras come in a range of costs and are available with 300–500 lines of resolution. Higher resolutions make distinguishing fine details and recognizing people at a distance easier.

The amount of light required to obtain a reasonable image is called the lux rating. 1 lux is approximately the light from one candle measured from 1 meter. Typical camera ratings range between 0.5 and 1.0 lux.

Monitors

Monitors are cathode-ray tube display systems similar to computer display systems. They are used to display video information processed by the camera. Coaxial cable is used to connect the camera to the monitor that can be located in any area selected by the user. Monitors do not have a TV tuner and usually have better video resolution than standard television receivers. They can also be connected to programmable switchers that receive input from several cameras and show multiple images on a single monitor.

Closed circuit TV (CCTV) monitors are available for black-and-white or color display depending on the resolution and camera selection. Black-and-white monitors have resolutions in the range of 700–1000 lines, whereas color monitors are available with 350–400 lines. CCTV monitors are designed for extended 24-hour-per-day operation.

NOTE

Video surveillance systems for both home and commercial business use are referred to as closed circuit TV (CCTV) systems. The name is derived from the type of the system used for transmission over a closed circuit or private transmission circuit rather than a standard television broadcast system. CCTV is also used in a wide variety of applications for schools, business video conferencing, retail store surveillance, and gambling casinos.

Switchers

Switchers are devices used with multiple camera systems. Although primarily used in commercial building security and surveillance systems, they can be scaled to fit the needs of a home security system. They enable several cameras to be used with a single monitor. The switcher can be programmed to cycle through all the cameras in a surveillance system or dwell on each camera for a specified length of time, usually in the range of 1–60 seconds. Exterior sensors can detect movement and cause cameras to start recording the image on a VCR.

Quads are special devices that enable the viewer to simultaneously record and monitor four cameras. It does this by splitting your screen into four sections. The normal configuration for connecting a quad switcher with a sensor and a VCR is shown in Figure 3.6, which illustrates the connections between a quad, a monitor, and four surveillance cameras. The monitor can view all four images at the same time.

Figure 3.6Figure 3.6 Quad camera switcher.

Pearson IT Certification Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Pearson IT Certification and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Pearson IT Certification products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.pearsonitcertification.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020