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Alarm Code Glossary of Remote Site Monitoring Acronyms

By Andrew Erickson

June 24, 2023


Remote site monitoring can sometimes seem like a language all its own. In the interest in brevity and for proper display on smaller LCD screens, a variety of alarm codes are output by monitoring gear and by your other devices themselves.

These codes provide crucial information about the status and performance of your network elements, so understanding them is critical for any telecom professional.

That's why I've compiled a comprehensive glossary to help you decipher the most commonly encountered alarm codes in remote site monitoring.

These first 15 terms are the most common. I'll dig deeper to define less-common terms in future articles.

The Top 15 Remote Site Monitoring Alarm Codes:

  • Fault Alarm or Fuse Alarm (FA): A Fault Alarm indicates a failure or malfunction within the system. This may range from minor issues, such as a loose cable, to severe problems, like a total system shutdown. Remember that the acronym "FA" can have other meanings, also. On DPS Telecom RTUs, for example, "FA" is used to indicate "Fuse Alarm". That simply means that a fuse must be replaced.
  • Critical Alarm (CA): A Critical Alarm signifies a serious issue that requires immediate attention. This type of alarm often signifies an event that could lead to significant network disruption or even total network failure if not addressed immediately. The T/Mon alarm management platform is one example of a device that uses the standard Critical/Major/Minor/Status system for reporting alarm severity.
  • Major Alarm (MA): This alarm type refers to significant issues that don't pose an immediate threat to overall network operations but should be addressed promptly to avoid further complications. You might be able to delay the fix for a Major Alarm until morning rather than paying for an overtime emergency.
  • Minor Alarm (MNA): Minor Alarms are for less urgent faults that do not immediately affect the network's functioning. They indicate situations that should be fixed to maintain optimal network health but do not require immediate action. It's common to delay handling of a Minor Alarm until your next scheduled or unscheduled visit to the site in question.
  • Indeterminate Alarm (INA): These alarms are generated when the system detects an abnormal condition but cannot pinpoint the exact nature of the fault. This notification doesn't tell you exactly where to go looking, but it does tell you that you should go looking.
  • Standing Alarm (SA): This type of alarm remains active until the problem causing it is resolved. Returning to our T/Mon example, T/Mon has two primary screens used for monitoring. When you want to have an up-to-the-minute picture of what's going on in your network, the "Standing Alarm Screen" is where you go to get that.
  • Cleared Alarm (CLA): A Cleared Alarm means that the system has recognized that a previously detected fault has been rectified and that normal operations can resume. You will not see clear events on T/Mon's Standing Alarm Screen because, by definition, a Cleared Alarm is no longer standing. You can see clear events on T/Mon's COS (Change of State) Screen. Both T/Mon screens use the same data as input, but they present it differently. Imagine you have a door alarm that sets and clears 10 times, then sets one more time and has not cleared yet. On the Standing Alarm Screen, there will be just one entry for the currently standing door alarm. On the COS screen, however, you'll see all 21 changes of state (10 alarms interlaced with 10 clears, then the one final alarm COS).
  • Environmental Alarm (EA): Environmental Alarms relate to the environmental conditions of the network site, such as temperature, humidity, and power supply. I see younger staff at my clients' companies forgetting to monitor this sort of thing in favor of more specialized network performance. I have to provide gentle reminders that, without power or during a thermal shutdown, all network performance is "multiply by zero". You must have a basic foundation before advanced performance metrics matter at all.
  • Communications Alarm (COMA): This alarm type signifies a communication-related problem, such as a network connectivity issue or a failure in the communication lines. DPS devices will notify you when a network interface is offline (using a second interface or an alternate path), when a poll or a response has not been received in a while, or when messages are received with unintelligible content. Oddly enough, the eerie "COMA" acronym is a useful term to remember that a device is unresponsive.
  • Security Alarm (SEC): These alarms are triggered by physical security breaches, like unauthorized access to the network site. The DPS Building Access System (BAS) has one example of a door alarm that would count as an SEC. This extends beyond a simple contact closure, as a door opening within the context of a valid proximity badge tap is nothing more than a Status Alarm.
  • Power Failure Alarm (PFA): This alarm is triggered when there's a power disruption, indicating that the system has switched to a backup power source or has ceased functioning due to lack of power. If a device has a backup battery and still has connectivity during the power loss, it can report this state itself. More commonly, the device will be offline - but other monitoring equipment can notice its absence. This can take the form of a polled architecture, where the central master (ex. T/Mon) is constantly asking the remote devices (ex. NetGuardians) for status updates on a loop. A device that reports new alarms or simply "no changes" is online, while a few seconds of silence would indicate a device that cannot be reached and demands attention.
  • Battery Backup Alarm (BBA): The Battery Backup Alarm activates when the system switches to its battery backup due to a power outage. It can also indicate when the backup battery level is critically low or malfunctioning. This is a subset of PFA (Power Failure Alarms). It's fine to be running on a spare tire, perhaps even for an extended period. BBA alarms inform you that you have entered this state so you can "meet the moment" with whatever urgency is necessary.
  • Hardware Failure Alarm (HFA): These alarms indicate problems with hardware components within the network infrastructure. This could include issues such as a faulty network card or a failed server component. These are commonly the type of alarm that classically would be reported via a summary contact closure. In the age of protocols like MODBUS, however, you can get very precise detail like "Card 7 Offline" or "High Noise on Card 4".
  • Software Error Alarm (SEA): This alarm is triggered when there's a malfunction, bug, or crash in the system's software. It could denote problems with system programs, operating systems, or application software. This implies that there is still enough functionality for the system (or perhaps a connected system) to report the problem at all.
  • Temperature Alarm (TA): A Temperature Alarm is an example of an environmental alarm that gets activated when the temperature in the equipment room gets too high or too low. It's crucial for preventing equipment damage due to overheating or freezing conditions. Temperature alarms can be driven by either discrete sensors (with a pre-set or fixed trigger point) or analog sensors (with software-controlled threshold(s) to trigger an alarm state)

Get Help with Your Alarm Codes

At DPS, remote monitoring is our focus 100% of the time. We can help you get your bearings, no matter what brand of equipment you're using.

Just give us a call at 1-800-693-0351 or email sales@dpstele.com to speak with a DPS engineer today.

Andrew Erickson

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 17 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and opt...