Public Safety Systems

What Are Public Communication Systems?

Public Safety Communications Systems (PSCS) are wireless communication systems that are used by first responders and emergency personnel such as fire rescue, law enforcement, homeland security, disaster response agencies, and within the medical field. These systems were designed to enable the above professions to prevent and respond to events that threaten the lives of people or the safety of their property.

Early Public Safety Communications Systems were radio systems created and deployed by Motorola in the 1930s. They were used by firemen and policemen for consistent communication in emergency situations. The Motorola company still provides much of the technology used in our Public Safety Communications Systems today.

Public Safety Communication Systems work by enabling and ensuring that radio signals can penetrate through the walls of various buildings. This would include areas where radio frequencies (RFs) have difficulty penetrating, such as elevators, stairwells, basements, and thick-walled or shield areas.

Today’s first responders, emergency teams, fire rescue, law enforcement, etc., rely on dependable voice communication. They’re also increasingly beginning to rely on data, location information, and telemetry—which allows for a quicker response time during an emergency situation.

All of these tools enabled by cellular technology are crucial to saving lives during emergency situations, which is why there’s a requirement under the National Fire Protection Association (NFPA) and the International Code Council (ICC) that all in-building wireless communications systems be up to a particular code and follow compliance as not to interfere with emergency response signals.

How Does It Work?

Public Safety Communications Systems work much like distributed antenna systems (DAS). They are comprised of signal inputting and signal distributing sources that convert and transmit radio frequencies over a network of antennas to allow singular devices to connect to the network. Public Safety Communication Systems typically utilize bands of radio frequencies within the VHF and UHF (45MHz, 150MHz, 220MHz, 400MHz, 500MHz) parts of the spectrum as these are voice-carrying frequencies. These frequencies were typically allocated between fixed base stations and vehicle-mounted, land mobile, or portable transceivers (think: Walki-talkies, police radios, scanners, etc.)

Today, Public Safety Communications Systems use digitally-based public safety frequencies and systems to expand their bands up to 700 MHz and 800 MHz. This is what allows for both voice and data transmission and communication. A Public Safety DAS network is set up exactly like a normal DAS network; only it includes much higher bands of radio frequencies for uninterrupted voice communication.

Installation And Requirements

Public Safety Communications Systems have specific code, compliance, and coverage requirements as well as installation requirements.

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General Requirements for PSCS

The most general requirement for a Public Safety Communications System is to remain within compliance. That means that any bi-directional amplifier (BDA) or radio enhancement system (RES) within a building cannot cause any interruptions with the public safety radio system.

It must also be completely compatible with all RES and BDA systems.

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Radio Coverage Requirements

Critical areas, such as emergency command centers, elevators, standpipe cabinets, exhibit routes, and any other areas noted by the AHJ (authority having jurisdiction), must have 99% coverage.

General areas, which are any areas not deemed as “critical,” must have 90% coverage.

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Signal Strength Requirements

All outbound and inbound signal strengths must be at -95dBm. The signal strength measured at the site’s repeaters must be adequately equipped to account for amplifier gain between antennas and receivers so the signal strength’s value can be translated into the correct carrier-to-noise ratio.

Buildings that already meet the signal strength requirements without the use of a BDA do not need to worry about signal booster installation.

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System Component Requirements

The Federal Communications Commission (FCC) must approve all signal boosting equipment
used within a building.
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System Frequency Requirements

Public Safety Frequencies are usually specified by the local public safety agency or AHJ. Any and all BDA’s used within a building are required to have the capability of re-transmitting the local Public Safety Frequencies.
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Building Maintenance Requirements

Upon installation, building owners are required to have service contracts for regular maintenance as well as emergency repairs. All repairs must be carried out within a two-hour window from the time of notification.
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System Monitoring and Testing Requirements

An automatic monitoring system with a dedicated command panel located in the emergency center is required in each building. It must be capable of detecting any signal boosting failures or antenna malfunctions and alarming the emergency center immediately.

There are also three types of mandatory testing that are to be carried out under specific codes and requirements. That includes annual testing, system testing (by the building’s owner), and acceptance testing by the AHJ.

Overall testing includes voice quality evaluations, building grid coverage, and the signal strength within each critical area.

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Power Supply Requirements

Every building is considered vulnerable to losing its primary source of power in an emergency situation such as a fire. Therefore, a backup power source is required. All critical buildings must be equipped with one or both of the following:

  • A stand-alone generator with an automatic failover
  • A 12-hour backup battery with the capacity to power all BDAs within the building

All backup power sources are required to carry on operations without power failure or interruption.

Sensitive radio equipment should also be protected during emergency situations. All radio and electronic equipment must be kept in National Electrical Manufacturers Association (NEMA-4) enclosures. These mandatory enclosures will water-proof and protect the sensitive equipment.

Nationwide Communications Services

Nationwide Communications Services is an industry leader in implementing digital technology solutions. We specialize in reliable structured cable installation and can take care of all your DAS and Public Safety Communication Service installation needs. With today’s ever-changing communication environment, you need to have options when it comes to your connectivity needs. Nationwide Communications Services can help you explore your options.

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