The Heart of the System

A security system's alarm control panel is similar to a central processing unit in a common computer system. It typically contains a motherboard with a set of screw terminals, one or more plug-in input/output bus connections, and accommodations for additional peripheral devices. Additionally, these systems contain firmware/software that an alarm technician programs on-site or remotely according to a client’s individual needs using a laptop, personal computer or a keypad.

Programming can use upload/download technology similar to that of a PC. Equipment manufacturers install a modem on the motherboard, and the connection is made with either the public switched telephone network or a voice over Internet protocol data network connection.

A modern control panel

Today’s alarm systems usually are designed to expand beyond their out-of-the-box capacity. If you recall, the motherboard contains a data bus connection to which additional expansion boards can be connected. In many cases, the technician can add four to 16 zones of additional capacity as well as two-way voice, access control, ancillary relays for external control, and other features.

Some systems allow the technician to add wireless connectivity, which helps with door and window transmitters, wireless motion and glass break detectors, radio-based smoke detectors and other devices. This type of panel is commonly called a hybrid because it provides both hardwired and wireless connectivity. In some cases, it requires a separate radio receiver module installed inside the panel, included in a keypad or located elsewhere in the building.

Making the radio receiver external to the alarm control panel has its advantages. First, the point of reception to all the transmitters in the structure can be centralized. This helps ensure receptivity in larger facilities. Wireless connectivity also allows usage of repeaters or multiple receivers, positioned in multiple locations throughout the structure.

Many alarm panels also accommodate card readers for door control, which requires the use of auxiliary relay modules for electric lock control. In an addressable system, this requires assigning a unique address to each relay module and specifying that relay. In a conventional alarm panel, relays can be connected to the keypad bus or a separate data bus to which many expansion boards can be added.

Partitioning saves space, money

Security companies and low-voltage contractors that install alarm systems for multiple tenants in single buildings know how time-consuming and cluttered things can get in a utility room when you use an alarm panel for each tenant space. Aside from all the cables, housing these alarm control panels in a room already filled with equipment can be challenging.

Alarm technicians and building owners should plan ahead when it comes to protection for multiple tenants. For those who plan ahead, there are systems that allow partitioning—the protection of multiple spaces using a single panel.

Partitioning saves space, time and money for installers, owners and tenants. For example, when more than one alarm control panel is used, technicians must install as many telephone lines and RJ31X jacks as there are panels, instead of one phone line and RJ31X jack for a single partitioned panel. Using the nonpartitioned method costs the alarm company more money, and these costs are passed onto the client. Partitioning uses less material and also saves a ton of labor money.

A single alarm panel can report alarms and supervisory conditions in more than one tenant space using multiple subscriber accounts—one for each tenant space. The alarm company can also monitor all tenant spaces using a single subscriber account, which saves money.

Where tenants are responsible for their own security arrangement, the central station usually requires a subscriber call list for each tenant. Where there is only one subscriber call list, only the owner of the building will receive a call when an alarm or trouble condition occurs in any of the tenant spaces. In this case, a partitioned arrangement works best when the owner subcontracts with a security guard force.

User interface

Alarm panels today can provide from two to 16 partitions. For every partition, there must be a means of user interface or system control, commonly accomplished through a keypad.

Every keypad in the building is assigned a unique identification number during programming. The technician then assigns each keypad to a specific partition in the alarm panel. When tenants enter their spaces, they must key in a PIN to disarm that portion of the system. Multiple users can be assigned to each partition, so different people can arm and disarm it.

Another setup allows arming and disarming a partition through a single keypad in a facility’s common area, such as the lobby. Any tenant can use this keypad to arm or disarm the entire facility—an effective strategy for a small building.

A third arming/disarming method combines these strategies: users first access and disarm the common portion and then their specific partition.

The alarm control panel is a complicated, but necessary, part of a building system, similar to the function of the heart.

COLOMBO is a 33-year veteran in the security and life safety markets. He is director with and a nationally recognized trade journalist in East Canton, Ohio. Reach him at

About the Author

Allan B. Colombo

Freelance Writer
Allan Colombo is a 35-year veteran in the security and life safety markets. He is director with and a nationally recognized trade journalist in East Canton, Ohio. Reach him at

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