How Radio Provides a Lifeline to Fire Station Alerting Systems

By April 27, 2015Uncategorized

First responders can have the best equipment and training, but all that is of no use without clear and timely communications about incidents. While IP networks provide a new and effective communications path, life-critical emergency communications need to consider every contingency. Radio, the staple of emergency communications for generations, has been and continues to be a key element of first responder systems – such as those used for fire station alerting. It’s a reliable way of delivering incident information – both voice and data. In this post, we explore how:

  • Radio can be incorporated into a fire station alerting system (FSAS)
  • Radio communications have evolved
  • PURVIS integrates radio into its FSAS
  • Considerations when selecting an FSAS relative to radio communications

Radio as a primary communications path

Every fire department has evolved their use of radio communications to best suit their needs. As a primary communications path, for instance, a single radio channel is used by some departments for dispatching, or when communicating back to the command center from the scene of an incident. Other departments use multiple radio channels – one channel for dispatch and switch to another channel for operations or tactical purposes, such as reporting while on scene.

Increasingly, counties and municipalities that have consolidated their first responder systems often take advantage of the consolidation initiative to build or leverage an IP-based network path – whether it be fiber-optic, copper, or high-speed cellular. Nevertheless, the likelihood that every station in the district has access to this network is small.  So this primary network strategy can be augmented with the additional ability to handle dispatch for smaller or strictly volunteer-based stations using radio.  This radio channel can be configured to deliver voice as well as the data that is necessary to drive the station alerting devices that may be in place at the station.

With the radio network in place, PURVIS system can send text-to-speech over the air so anyone in the station with a radio will hear it. Any personnel in the field, at home, or in their cars monitoring that dispatch line will also hear the announcement.

Radio as a backup

According to NFPA 1221 two data paths are required. While an IP data path is a good choice for primary communications, a legitimate secondary communications path is audio over radio. In fact, this is a typical use scenario. When the IP network goes down, the FSAS system can bypass the IP network and instead communicate via radio. This makes it possible for the system to remain viable, activating devices at the station, such as the printer and lights.

PURVIS FSAS can send either data, or a voice alert over the radio path. For example, a data modem at the station would use radio frequencies to receive alerts and incident information. In such cases, the FSAS unit at the station would treat radio as an alternative path for the incident data.

What’s the frequency when it comes to Project 25 (P25)?

The P25 standards were largely developed to ensure reliable and interoperable digital radio communications. In essence, P25 is a digital version of analog radio. While communications over analog radio are reliable, the sound quality can suffer due to the signal strength. Sound quality over digital is superior, however, digital transmissions can fail altogether without a strong radio signal. This is not usually a problem in cities with robust infrastructure featuring multiple broadcast points and repeaters that help deliver a strong signal. The PURVIS FSAS provides the option of delivering both audio and data over radio using P25, allowing counties and departments to take advantage of this latest standard. As a result, counties can ensure radio systems communications systems are interoperable within a jurisdiction, or in departments and agencies in the same community.

How PURVIS integrates the various forms of radio into its FSAS

The PURVIS FSAS server interfaces directly with dispatch equipment.  In some scenarios, the system is integrated to a dedicated radio, allowing it to send audio-over-radio alerts to stations and field personnel. If the radio channel (or talk group) is currently in use, the system can detect if the radio channel is busy. In these cases, it delays alerts until the channel is free, so the dispatch center can be certain an alert was sent.

Some jurisdictions use a Telex device/radio gateway with many radios to alert multiple departments or stations. This setup is controlled via a common console. Once the PURVIS FSAS is in place, it can be integrated with the Telex device(s) to dispatch units with the ability to determine if the channel is currently in use.

Charleston County uses the PURVIS FSAS in its multi-jurisdictional dispatch center serving 13 departments and 78 stations over 14 different radio channels. While 72 of the stations are equipped with a data network path, the other six unmanned stations require audio-over-radio communications. The PURVIS system delivers automated text-to-speech to those six stations as the primary alerting path, and sends audio-over-radio to the other 72 stations as the backup. All of this originates from the same dispatch center.


What to look for in a world-class FSAS radio deployment

Not all FSAS are equal when it comes to support for radio communications. With that in mind, seek out a system that:

  • Enables automated communications.
  • Incorporates redundancy and monitoring using the latest technologies to minimize downtime.
  • Supports multiple communication paths – this eliminates the need for personnel to manually select a server for alerting and minimizes timeouts before an alert is sent.
  • Scales easily and affordably because it’s based on non-proprietary hardware.
  • Is provided by a company with the capabilities to integrate the system to suit the department or county’s unique requirements.
  • Supports multiple jurisdictions and their requirements, such as two radio alerting paths out of single dispatch center and alerting multiple departments, or sending a combination of tones so stations hear alerts specific to them.

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