IP networks, whether Ethernet, Wi-Fi, or Internet, have rapidly spread from business-only uses to encompass residential, light commercial, and multi-building campuses. When connected to the Internet, data, video, and voice information can be transmitted around the world.

Electronic security installations can utilize these data “highways” to transmit video, alarm transmissions, access control, and other communications, all by connecting to existing cabling and networks.

For intrusion detection systems, IP networks can be used to transmit alarm signals to a central monitoring station. The ability to transmit different types of alarm signaling over IP networks is only limited by the installing company’s imagination, and knowledge of network topology, devices, and addressing.

When integrated with video imaging and/or access control, an IP-based security system can provide complete monitoring and control of multiple facilities, while greatly reducing new cable installations and signal transmission costs. If the IP network is already in place, there is no extra cost for the alarm system’s data to be carried over it.

One of the primary benefits of IP networked alarm signals is that signals can be received and processed from remote locations by sending the information over the Internet. By concentrating the monitoring of a number of buildings into a single location, client costs for guards are reduced. Also, IP alarm signals can be monitored at multiple locations, providing an alternative in the event that the primary monitoring station has been disabled.


The Internet is becoming the preferred conduit for the transmission of alarm signals to the central station. As clients change over to Voice over Internet Protocol (VoIP), traditional digital communicator-equipped alarm systems must be reconnected to the VoIP adapter, and may have difficulties passing their analog alarm messages over the digital IP network. (See related article, “A Gathering Storm,” SDM August 2004, p. 56; and online at www.sdmmag.com.) Major alarm equipment manufacturers are providing IP alarm transmitters that connect a control panel’s alarm outputs directly to the local area network (LAN) and Internet for communication.

The key advantage of IP transmitters is higher security, as the devices can be polled by the central station every few minutes for functionality. IP transmitters are approved for use for fire alarm transmission, UL Standard 864, as well as UL Standard 1610 Intrusion Systems, provided that they are properly installed, programmed, and monitored. Using IP alarm transmitters also eliminates issues of trying to connect and communicate alarm signal transmissions over VoIP connections.

At the central station, supervisory and alarm messages from IP alarm transmitters can be received by a properly equipped alarm receiver, which usually requires a specific line card connected to a broadband Internet connection. As processed by the central station’s alarm monitoring software, there is no difference between the receipt of IP alarm messages and standard digital communications. IP alarm transmitters must be programmed to generate polling messages that confirm remote transmitters’ functionality with the central station on a selectable time basis. UL installations will require a specific maximum time between polling messages.

Connected to an alarm control, IP transmitters are linked to the Ethernet network within a building, transmitting alarm and supervisory signals to the central station over the Internet.

IP Transmitters/Receivers

There are a number of issues that alarm installation companies must address to successfully install an IP alarm transmitter at a particular location. The first is product selection – which IP transmitter should be installed?

The alarm industry has become dependent on the telco-connected digital communicator, which can be programmed to provide a wealth of different types of alarm signals, such as user IDs, open/close, system troubles, and specific zone or device alarm activations. An IP alarm transmitter can provide the same depth of information to the central station, provided that it is properly matched for the control/communicator at the client’s location.

The selection of the proper IP transmitter to use is very often dependent on which specific burglar alarm panel is being connected. Major manufacturers such as DMP, Honeywell Security, Bosch Security, DSC and GE Infrastructure, Security; provide specific IP transmitter interfaces for their popular products, allowing a relatively simple connection to the panel, and a full range of reporting options. (Please see “IP Transmitters Compatibility Table” for major vendor product compatibility.)

If no “matching” IP transmitter is available for a particular panel, the panel can be replaced, or there are other options. An installing company can use a Dialer Capture Module (DCM), available from Bosch Security. This device connects to the digital dialer outputs of the panel, and emulates a digital receiver. When an alarm signal is transmitted, the DCM accepts the digital output, transmits the signal over the IP network to the central station, and simulates the alarm receiver’s acknowledge messages to the alarm control, after the successful transmission of the IP alarm signal.

If the client’s control panel provides auxiliary voltage triggers or relay outputs, these may be interfaced to IP alarm transmitters that accept those types of inputs. The DSC T-Link TL250 IP transmitter from DSC provides a number of possibilities for connection to existing panels, as well as mating to DSC controls. If the client’s existing control panel only has simple pulse/steady bell outputs, those can be connected and transmitted as separate messages. Controls with separate zone or status outputs also can be interfaced with up to four separate reports (or 12 if the DSC T-Link TL250 is equipped with an expander board). This product also will function as a stand-alone IP alarm/status transmitter, allowing the connection of environmental sensors, such as temperature monitors, or any other sensor that provides an output.

Current IP transmitter products will only communicate with receivers manufactured by the same vendor. So the type of central station receiver that will process the signals may well determine selection of a transmitter vendor. If, for example, the central station uses a Bosch/ Radionics receiver, Bosch IP alarm transmitters must be used.

Honeywell provides IP alarm transmission capability through the AlarmNet network, which also provides long-range radio and cellular alarm capability.


There are several issues to consider when installing an IP alarm transmitter. The first is the data connection to the network. A network connection, typically a UTP Cat 5e or higher quality, must be available to connect the IP transmitter, located in or near the alarm control panel, to an available port in the IP network. This may be an otherwise unused RJ-45 jack on the wall, or new UTP cable may need to be run to bring the network to the alarm control. It’s possible that the alarm panel may be installed within the main cross connection or horizontal cross connection room, making connection to the network a simple process.

A typical connection of an IP transmitter to an alarm panel is illustrated on the previous page. Power for the IP alarm transmitter typically will be provided by a connection to the alarm panel.


Once the IP transmitter is in place, it must be programmed to the proper central station ID, as well as other selectable features. Programming methods will vary with different manufacturers, as well as the particular central station receiver being used. Although a particular IP transmitter may be programmable over the network, use of a laptop computer will provide the technician with a quick connection to the transmitter, as well as easy viewing of the transmitter’s indicating LED array. Some vendor’s products are programmed with a specific device, such as the Honeywell/AlarmNet 7845I, which uses the 7720P programmer, which also functions as the programmer for Honeywell’s AlarmNet radio and cellular products. Programming through a “mated” control panel’s keypad is available from vendors such as DSC.

Along with programming the IP alarm transmitter, the control panel outputs may need to be “turned on” via a keypad or programming selection and the central station receiver must be programmed to receive alarm signals and supervisory messages from the field device.


Network devices must each have a unique IP address, which allows it to communicate with other devices on the local network, and access the Internet. These addresses are in the format of:


with no value higher than 255 for each group of numbers separated by periods.

IP addressing is provided by two different methods, which is a selectable choice by the system operator. Static IP addresses are fixed, and will be provided by the IT manager to the alarm installing company. This address is programmed into the IP alarm transmitter.

The other approach for IP addressing is DHCP, which stands for “Dynamic Host Configuration Protocol.” Controlled by a router or gateway, network devices are assigned temporary IP addresses for a specific amount of time, which is called a lease. DHCP is very commonly used in networks big and small, as it greatly reduces the amount of record-keeping and verbal communication between computer users and IT management personnel. Most users don’t care what their computer’s IP address is, as long as it works on the network.

IP alarm transmitters can be programmed to accept DHCP addressing, which simplifies the programming of the alarm product.

Some network administrators will use both static and DHCP addressing within the same network. For example, desktop and permanent computers may use static addresses, while the router may be programmed to provide a set quantity of DHCP variable addresses for visiting Wi-Fi laptop users.


A handy tool for general network use is the ping command, which can be used to test for the connection and accessibility of local area network devices and Internet-connected computers.

For example, once an IP alarm transmitter has been programmed for a static IP, to check for its connection to the local network, go to another computer connected to the network, click “Start” in Windows 2000/XP, click “Run,” type COMMAND, and a window will open on the computer screen. At the command line, type ping 111.222.333.444, using the IP address that has been programmed into the alarm transmitter. If the screen displays “timed out,” then the transmitter isn’t properly addressed, connected to the network, or perhaps there’s a power problem. If responses are received from the transmitter, then addressing and connection are OK.

The same type of test can be performed to ensure that the path from the LAN to the alarm receiver has been cleared. Using the Internet IP address of the alarm receiver at the central station, use the same ping sequence as detailed previously. If responses are received, the computer being used can communicate with the central station receiver, which would indicate that the path for alarm signal transmission has been cleared through the network router, which provides the connection to the Internet.

Backup & Downloading

While IP alarm transmitters provide much higher security than telco-connected digital communicators, connecting a telephone line to the digital communicator outputs of a control panel can provide dual and/or backup reporting. This would be desirable in the event of IP transmitter or network failure. Client or telephone network use of VoIP may negate this feature, as some digital formats will not pass through this digitized voice protocol, and a VoIP connection often becomes inoperable when the computer network goes down.

The vital technology of remote downloading of control panel functions can be affected by the installation of IP alarm transmitters. If the IP network is the only communication connection to a particular panel, telco-based downloading will not be available for that system. Some vendors, such as DSC, provide for remote downloading capability over the Internet, by using a specific software set in the downloading computer.


IP transmitters are perfectly suited for private network or large enterprise monitoring applications, where a client wants to privately monitor a number of locations, whether within a single campus, at far-flung locations around the globe, or a combination of the two. Using IP alarm transmitters leverages the existing network cabling plant and Internet connections that are already being supplied for use for the client’s data transmissions. Some transmitters can be programmed to transmit alarm signals to multiple IP addressed receivers, providing redundant or backup transmissions. This is a powerful feature, as critical alarm messages can be transmitted to a traditional central station, while supervisory or less important transmissions (along with critical burg/fire messages) can be received and responded to by the client’s own monitoring staff.

Signal Encryption & Security Issues

With the ready availability of literally millions of Internet connections, alarm equipment vendors have built sophisticated signal encryption into IP alarm transmitters and receivers, to defend against a rogue transmitter being used to emulate “I’m OK, no alarm signals here” polling signals emanating from an IP alarm transmitter at a target installation. Such encryption programs include the use of “keys,” which are held at both the receiver and transmitter. When an encrypted communication is received, the key is used to convert the garbled signal into its original state. Typical encryption programs used are “Blowfish,” which uses a 1024 bit format, and 128 and 256 bit AES.

Programming of the encryption format to be used will be generally dictated by the products selected, and the encryption program used by the corresponding alarm receiver at the central station.

Author Recommendations

IP alarm transmitters provide much higher security of alarm signaling, and will become more popular as IP networks grow, and the traditional telco-based alarm monitoring paths mutate into hybrid VoIP/analog networks. IP alarm transmitters are also new and different types of devices, and require knowledge of IP, networking, and structured cabling systems for successful installation.

How should an alarm installing company prepare itself for installing IP alarm transmitters? Here are two recommendations:

TRANSMITTER SELECTION – Determine which IP transmitter(s) will best function with the existing panel population, and central station receiver.

PANEL SELECTION – Consider which alarm control panels should be installed on new jobs, so that the migration path to IP transmission is a simple process.

Installation of IP alarm transmitters can be tricky, as new programming techniques and communication methods are needed. An intelligent approach for alarm companies is to practice at the office, by bench-test connecting IP alarm transmitters to the panels the company typically uses in the field. Once the glitches have been surmounted, field installations can proceed without undue difficulties.

TIP: Avoid Losing the Signals

If the IP alarm transmitter is connected to the alarm panel via relay outputs or alarm triggers, the variety and amount of individual alarm messages available for transmission to the central station will be greatly limited, as compared with standard

digital alarm signals. Detailed signals such as individual zone alarms, user-specific open/close reports, and other such expansive alarm and supervisory signals may be impossible to pass to the IP alarm transmitter.

TIP: Expect Pricing to Come Down

As when other technologies have been introduced into the electronic security industry, the first generations of IP alarm transmitters are not inexpensive. Typical costs are in the range of $250 or more per unit, although manufacturers will soon be releasing devices at substantially reduced costs.

TIP: Clear the Path to the Internet

The dangers of hacker attacks have caused network manufacturers and users to implement a number of measures to restrict transmissions to and from the Internet. Such protection can be in the form of firewalls, which can selectively block data traffic, and in router or gateway settings, which can allow or deny access to the Internet by specific network devices connected to them.

If such network security measures are in place, a pathway to the Internet must be cleared for the IP alarm transmitter, allowing it to both transmit to the Internet and receive acknowledgements of transmissions from the remote receiver.

If the client has an IT department, the programming and specifications of the IP alarm transmitter will provide the IT manager with the necessary information to open up the

necessary communications paths to and from the transmitter. In residential or small business applications, it is likely that the client may have little or no knowledge about the functions

of his router or gateway. In this case, the alarm installation personnel must have a working knowledge of networking, firewalls, and other issues to be able to “clear the path” for

IP alarm transmissions.

TIP: Test Alarm Transmissions

As with any type of alarm signal transmission technology, complete and thorough testing of all alarm signals to the central station should be performed by the installer before completing the installation and leaving the jobsite.

Alarm Activations & Outputs

Does your client want to activate, monitor, or control equipment over the Internet?

Any type of alarm input can be monitored and controlled using network-interfacing equipment. A variety of vendors provide IP addressed modules to which contact devices, such as motion detectors and contacts, can be connected, enabling them to be monitored thousands of miles away over the Internet. As an example, the Mavix Media Racer products provide analog CCTV input, alarm point monitoring, access control communication, two-way audio, and relay output control all within a single IP-addressed module. Using devices of this type, clients or monitoring companies can respond when a person or vehicle approaches an entrance, use video to verify the activity, speak with the person, and activate a door strike or gate to allow entry. Thousands of these modules can be monitored from a single or multiple locations, using software that provides graphic maps and/or building diagrams overlaid with icons depicting the various security devices connected, and their current status. More information about Mavix can be found at www.mavix.com.

Although such end-to-end systems provide device supervision via periodic polling from the monitoring PCs to the remote devices, it is important to note that typical IP addressed devices are not supervised in the same sense as alarm contacts, smoke detectors, and other sensing devices that are familiar in the alarm industry. If an IP-addressed computer is unplugged from the network, no alarm will be sounded. The only indication that the computer is no longer connected is when that computer’s operator tries to reach the network and doesn’t, or another computer tries

to access the disconnected device. For higher security, consider using a stand-alone IP alarm transmitter such as the DSC T-Link TL250.

It’s realistic to believe that in the near future, a new generation of IP-addressed alarm contacts, motion detectors, and other sensors will become available. Such devices will be easily connected

to existing network cabling, providing quick and inexpensive installations. Industry manufacturers already have a good handle on point addressing, with companies such as Honeywell/ADEMCO and Bosch/Radionics having delivered addressable alarm components for over a decade. As industry vendors apply their addressing knowledge to the

IP arena, it’s only a matter of time before these products become a reality.