Security & Fire Alarm Panels: A Word On POTS/Fiber

Fire Alarm and Security Alarm panels are great devices.  Their central brain system allows a bunch of independent systems (smoke detectors, CO2 detectors, heat detectors, gas detectors, door open detectors, etc) to all report back to a central location and then have the central location call out to the Police or Fire Department and relay exactly what is wrong at exactly what part of the building.

In theory this is great.

The only problem is: how do these devices communicate with the outside world (the inside world being your building, the outside world being everyone else).  The answer for us is: a phone line.

Not a data connection to the internet, or even a Fiber ONT, but literally POTS: plain old telephone service.  Yes, the 2-4-6 pair lines that carry voice to a carrier and then the carrier interconnects to other carriers to get people talking.

In this day and age, POTS should be dead.

Deploying copper POTS lines is, for the purposes of this discussion, infinitely more expensive than running Fiber to an ONT in the building and having all the phone lines distribute out from there.  That is to say: the cost of running one copper pair (or even a whole 66 pair terminal) is going to be more expensive than the cost of running a single line of fiber (which can carry hundreds to thousands of voice lines).

So why don’t we switch to Fiber ONTs?

Local law requirements dictate that the phone lines for signaling from Fire and Alarm panels cannot be dependent on local area power.  Even the panel cannot be dependent on local area power.  This is why you often see battery packs connected to the panels.  Those batteries can last 12-48 hours, depending on their charge level, age, and type.

I can see the argument: so long as there is no damage to the pole POTS lines are ALWAYS working.  There is no power to be concerned with.  That being said, the benchmark to beat is a maximum of 48 hours without power.

A single Fiber ONT with 2 12V batteries connected to it can remain powered on for 48-96 hours (again dependent on charge, age, and type).  This ONT can provide so many phone lines (way more than the 4 lines for Fire & Security at 2 lines per panel).  This means that the ONT would be providing network connectivity to the panel for almost twice as long as the panel would even HAVE power.  I don’t see how this isn’t becoming the de facto standard in security systems.

Why haven’t we switched?  I don’t know.  I’ve proposed it to my boss.  He said he’d look into it.

Disadvantages of Fiber ONT over POTS

  • ‘Limited’ Lifetime of ONT battery compared to always-on POTS.
  • Initial cost of rollout may be high.
  • Battery maintenance is a customer cost that does not exist with POTS.

Advantages of Fiber ONT over POTS

  • Lifetime of ONT battery may outlast panel battery (both in hours of on-time and length of time between battery replacements).
  • No need to waste technician time with antiquated end-of-life technology repairs.
  • Keeping up with changing technology advancements allows business operations to be un-interrupted for greater periods of time.
  • Fiber ONT is much more reliable than POTS in almost every metric.
  • Fiber ONT does not degrade over time (no static on lines assuming your in-building wiring is sound).

My time is cheap though, and switching providers can be expensive.  It may be simply a matter of “We’re paying you already so it’s cheaper for you to just keep wasting your time dealing with Verizon/Spectrotel and the phone lines than it is to get those systems replaced.”

It’s an answer.  It’s not a great answer, but it’s an answer.

And I suppose that’s good enough.

Leave a Reply