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Cell Phones or Two-Way Radios for Security Use?
The Need for Security Communications
Many organizations use security officers as a part of their overall security program. These officers make routine patrols, respond to security incidents, and provide other services to employees and to the general public. For security officers to work effectively, it is essential that they have a good communications system in place. This system needs to allow security officers to be summoned when their help is needed, as well as allow communications between security officers as they carry out their daily activities.
In larger organizations, there is typically some form of central security command center that serves as the hub of the security operation. In these cases, calls for security service are typically made to the command center, which in turn dispatches a security officer to the location where needed. For example, if an employee sees someone suspicious in the parking lot, she would call the number of the security command center to report the incident. The command center would then dispatch one or more security officers to the parking lot to investigate. The command center would monitor the incident, coordinate activities between security officers, and if needed, call in outside agencies for help.
Smaller organizations may not have a security command center and may only have one security officer on site at any one time. In these cases, employees usually communicate directly with the security officer who is on duty. For example, if an employee was locked out of his office and needed access, he would contact the security officer on duty and ask him to respond to unlock the door.
The two most common methods of security communications used today are the cell phone and the two-way radio. In the past, pagers were also commonly used but have now been mostly replaced by cell phones.
Security managers often have difficulty in deciding which communications devices should be issued to security officers: should they issue cell phones, two-way radios, or both? Within this article, we will discuss the advantages and disadvantages of both options and provide some ideas that may be helpful when planning your security communications system.
Two-way radio systems have been used for business, public safety, and security communications for more than fifty years. Prior to the introduction of cell phones, two-way radios were really the only option when you wanted two-way communications with someone on the go.
Two-way radios consist of two parts, a radio transmitter, and a radio receiver. These two parts are combined into a single unit known as a radio "transceiver". There are three types of radio transceivers: portable transceivers, mobile transceivers, and base station transceivers. The following is a brief description of each transceiver type:
Portable transceivers, often called "walkie-talkies", are hand-held units that can easily be carried by the security officer. These units are battery powered and have a self-contained speaker, microphone, and antenna. External microphones and earphones can also be used.
Portable transceivers typically have a range of between one and three miles depending on power, frequency, and the type of obstructions between units. Range within concrete or steel buildings can be considerably less.
Mobile transceivers are larger units that are designed to be mounted in vehicles. Mobile transceivers have an external microphone that makes using the radio while driving more convenient. Mobile transceivers are powered from the the vehicle's electrical system and typically transmit at a much higher power than that used by portable transceivers. Mobile transceivers also have an external antenna that is usually mounted on the roof or trunk of the vehicle. The combination of a higher transmitting power and an external antenna gives mobile transceivers a much greater range than portable transceivers; typically five to fifteen miles depending on conditions.
Base Station Transceivers
Base station transceivers are designed to be mounted at a fixed location, such as at the security command center. Base station transceivers typically operate at high power levels and use an external antenna mounted on the roof of the building. Base station transceivers can be provided with desktop microphones and speakers that can allow use of the radio from multiple locations in the security command center.
The typical security department would probably use a combination of transceiver types; portable transceivers would be carried by security officers, mobile transceivers would be used in security patrol vehicles, and a base station transceiver would be used at the security command center.
Two-way radio systems are available in several different frequency ranges. VHF high band (130 -174 MHz) and UHF (400 - 512 MHz) are the frequencies most commonly used for security purposes. Most security organizations use conventional analog two-way radio systems, although some very large organizations may use digital or trunked radio systems.
Many campuses are so large that they exceed the limited range of a portable two-way radio transceiver. To solve this problem, radio repeaters are often used. Radio repeaters are mounted at a high-point on the campus (such as at the top of a building or water tower) and extend the range of signals by receiving and retransmitting them. A repeater mounted in a very high place (such as on a mountaintop or high-rise building) can often allow portable transceivers to cover an entire city or county.
Some buildings are so densely constructed that they block out radio signals, preventing communications through more than one or two floors. To solve this problem, distributed antenna systems can be used within the building to pickup and and distribute signals between floors. These systems often use "leaky coax" type antennas installed above the ceilings.
Many large organizations may need to use a combination of both radio repeaters and distributed antenna systems to provide reliable two-way radio system coverage throughout their entire campus.
Cellular telephones ("cell phones") were first introduced about twenty-five years ago. Early cell phones were bulky and expensive and only worked in limited areas. Today, cell phones are small, convenient, relatively inexpensive and used by almost everyone from small children to senior citizens. Many of today's cell phones are "smartphones" that in addition to being used to make calls, can be used for email, text messaging, web browsing, listening to music and running application programs.
Unknown to many people, cell phones are actually a form of radio transceiver, This transceiver transmits and receives low-power radio signals to and from nearby radio stations known as "cell sites". These cell sites each cover a small geographic area and communicate with all of a given service provider's cell phones within that area. In suburban areas, each cell site may cover an area of several miles, while in dense urban areas, each cell site may cover an area of a quarter-mile or less.
All cell sites are connected to a central computer which manages communications between the cell phones and the sites. As a user travels down the road using his cell phone, the computer keeps track of the phone's location and automatically switches the cell phone to the nearest site. The computer can also adjust the phone's transmitting power so that an appropriate level of power is always used. When someone dials a cell phone number, the central computer routes the call to the the cell site nearest to where the cell phone is located and rings the phone.
Good cell phone coverage is now available in most metropolitan areas of the United States. Chances are very good that your cell phone will work almost everywhere in the outdoor areas on your campus. Indoor coverage is another matter. While cell phones usually work well in wood frame buildings, coverage can be spotty in concrete or steel frame buildings, except when standing near outside walls. Cell phone coverage in below-grade basements or underground parking garages can also be a problem.
To provide good cell phone coverage within all areas of large buildings, it is sometimes necessary to install distributed antenna systems similar to those used with two-way radio systems. These systems are usually custom engineered to meet the specific needs of the building. The cost of installing these systems is sometimes subsidized by the cell phone carrier if the organization is a significant customer.
Comparison Between Two-Way Radios and Cell Phones
Two-way radios and cell phones each have their advantages and disadvantages. Here is a brief comparison of each option:
Our Conclusions and Recommendations
It is our opinion that the simplicity, ruggedness, and reliability of two-way radios makes them the best choice for security officer communications in most situations. Just as law enforcement and other public service agencies continue to use two-way radios, we feel that most security departments are still best served by using two-way radios over other communications devices.
The only exception is very small organizations where there may only be one security officer on duty at a time. In these cases, a cell phone is probably the only communications option that makes sense.
Tips for Using Radios and Cell Phones
If you have questions about the use of two-way radios or cell phones, or need help in designing an effective communications system for your security department, please contact us.
(a) It is possible to make and receive telephone calls with a two-way radio if a telephone interconnection unit is provided at the radio base station. While these units were widely-used prior to the introduction of cell phones, they are rarely used today.
(b) It is possible to provide two-way radios that have an encrypted signal that cannot be easily listened to with a radio scanner. Radios that have this feature are more expensive and not commonly used in most security communications applications.
(c) Some cell phone providers offer a service that they claim provides "one-to-many" functionality. An example of one such service is Sprint/Nextel's Direct Connect. It is our opinion that these services have many limitations and do not fully replicate the "one-to-many" capability provided by a two-way radio system.
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