Alarms

Fire Alarm with Audio and Visual Annunciators

Description

Verbatim Alarm Monitoring Control System Raco Manufacturing, Inc.

Sensaphone 1104 Alarm Monitoring and Control System Sensaphone, Inc.

Attributes and Features

Intrusion Sensor Alarm

• Foil is inexpensive (it costs only a few cents per foot); and
  
• Would-be intruders know the premises are protected because the foil is easy to observe on the window/door.

• Foil can be difficult to properly install due to its fragile nature;
  
• Foil can be broken when windows are washed; and
  
• Foil may make the door or window unattractive.

• Switches are inexpensive;
  
• Switches are very reliable and do not require maintenance; and
  
• It is easy to install these types of devices.

• Lower security-type switches are easy to defeat using a strong magnet or a spare piece of wire.

• These systems have a low incidence of false alarms.

• Glass break detectors have are relatively complex to install; and
  
• One device is required per window.

• These systems are easy to install; and
  
• One audio discriminator covers multiple windows in a single room or space.

• An alarm can be triggered by other types of high-pitched sounds that are not caused by breaking glass; and
  
• These systems only alarm if the glass is broken. This means that the alarm could be bypassed if the glass is compromised by some other means (i.e., if glass is removed but not broken).

• This technology has low power requirements;
  
• Radio waves, sharp sounds, or sudden vibrations do not cause the system to alarm; and
  
• PIR devices are easy to conceal because of their small size.

• These sensors cannot cover the entire protected area at once; thus there are pockets within the protected area that are unprotected from potential intruders.

• These systems reduce false alarms because both sensors (or alarm channels) must simultaneously detect an alarm condition before an alarm is triggered.

• If one sensor is defeated, the entire system is defeated.

• The sensor is able to cover majority of a protected area, and has minimal "blind spots".

• These sensors have difficulty detecting movement in rooms that absorb sound waves (i.e., rooms with wall-to-wall carpeting or curtains);
  
• The sensors also have difficulty sensing fast or slow movements behind objects; and
  
• Certain sounds, such as telephones, can cause false alarms.

• They can be placed behind solid objects and thus they are easy to conceal; and
  
• When they are properly adjusted, they are not vulnerable to loud noises or air movement.

• Their extreme sensitivity makes them difficult to properly adjust;
  
• Movement beyond the protected area can trigger alarms, because microwaves can penetrate walls; and
  
• Fluorescent lights and radio transmissions can trigger alarms.

Dual Technology Motion Sensor GE Interlogix Sensors and Detectors

• Dual detection devices are less vulnerable to false alarms than are many other types of detector types because both sensors must be tripped to signal an alarm.

• Dual technology devices are more expensive than other types of detection devices; and
  
• Both sensors must detect the intrusion event for the alarm to be triggered. Thus, if one sensor is defeated, the entire system is defeated.

Photoelectric Smoke Detector GE Interlogix Sensors and Detectors

• Photoelectric smoke detectors react to visible particles of smoke. These detectors are more sensitive to the cooler smoke with large smoke particles that is typical of smoldering fires.
  
• Ionization smoke detectors are sensitive to the presence of ions produced by the chemical reactions that take place during combustion. This type of sensor readily detects hot gases with few smoke particles, such as those typically produced by fast burning/flaming fires.

• DACT is compatible with telephone technology and various calling features;
  
• This type of system can report a large amount of data about the alarm (account numbers, zone indicators, etc.) in addition to the alarm signal;
  
• Multi-zone reporting that identifies the exact location of alarm inside the protected facility can be set up using DACT;
  
• DACT can be used to remotely program controls to arm, disarm, and shut down the alarm system when needed;
  
• Technology to prevent intruders from seizing or jamming the telephone lines can be incorporated into DACT systems; and
  
• DACT can be used to activate listening devices or CCTV and transmit these data to a central monitoring station.

• DACT requires PSTN lines;
  
• There can often be line noise (static), which interferes with alarm transmissions;
  
• If an anti-jam feature is not in place, intruders can call the protected facility from another telephone and tie up the line; and
  
• The system can be easily compromised by intruders cutting or shorting telephone lines.

• This method uses voice-grade lines;
  
• The party lines are shared networks, which result in lower costs; and
  
• Two-way transmission is possible between the subscriber site and central monitoring station.

• It may be difficult to service party lines due to potential problems in identifying the exact location of the problem in the line;
  
• The entire party line could go down if there is a problem with one unit; and
  
• The network is vulnerable to interference from any one location, electrical noise and induced "jamming" signals.

• These systems do not depend on the availability of the PSTN.

• Alarm monitoring may be disrupted if there is a problem with the Internet connection.

• There is constant supervision of the line; and
  
• The system uses voice-grade lines.

• There is increased cost to the subscriber as distance from the hub increases; and
  
• The system depends on the availability of the PSTN.

• The lines are hard to compromise (shutdown, short, etc.) because they are constantly monitored;
  
• It is easy to service systems since there is only one customer per leased line; and
  
• These systems are easy to install.

• The type of alarm information that can be transmitted is limited;
  
• Leased lines can be costly;
  
• Older systems couldn't distinguish between alarm and line failures; and
  
• The cost of copper wire is high, and thus charges by the PSTN have increased.

• It is hard to compromise (shut down, short, etc.) direct connect lines because they are constantly monitored; and
  
• It is easy to service these systems since there is only one customer per leased line.

• Limited alarm or trouble information can be communicated from the subscriber site; and
  
• The cost of copper wire is high, thus charges by the PSTN are increased.

• There is continuous supervision of the line.

• There are a limited number of customers per loop due to voltage decreases as more customers are added, causing the current to flow below acceptable limits;
  
• Signal scrambling can occur if multiple sites go into alarm at the same time
  
• System costs may be high because the PSTN owns the lines;
  
• Breaks in the loop take long periods to repair because the location of the break cannot be identified easily; and
  
• The wiring can get crossed with the regular PSTN lines, creating garbled signals.

• The system uses voice-grade lines;
  
• Tape dialers have the ability to call multiple numbers (central monitoring station, fire, police, etc.); and
  
• Tape dialers can call a number more than once, thus increasing the possibility of a call being received.

• These system may experience mechanical problems (i.e., the tape may become jammed or damaged);
  
• The prerecorded recordings may be of poor quality and may be difficult to understand; and
  
• If call is not answered, the alarm could go undetected.

• Multiple transmission options are available; and
  
• The subscriber is not dependent on the PSTN.

• Trees and large buildings can block signals;
  
• The distance of the transmission is limited to the line of site;
  
• Transmitters tend to drift from the established frequency; and
  
• Other devices using frequencies near 900 MHz can impair signals.

• Alarms can be transmitted even if local phone service is down, providing that the system can "handshake" with a cellular tower site.

• These systems will not work where devices cannot receive a cell signal.

Cost

Glass Break Sensor GE Interlogix Sensors and Detectors

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