Introduction to Communications

Communications Introduction

Communication is vital.  It is the passing of information from one person to another.  This information can be a thought, a request, a need … anything at all.

An interesting thought was put forth about communications in a historical show about the Dark Ages in Europe: after the plague and the Viking hordes, there were not enough people left living in Europe near each other to share ideas and spark creativity.  The Renaissance had to wait until the population rebounded to create a density of shared ideas.  Hence, the lack of communication held back the advancement of European civilization after the fall of Rome until the Renaissance.

If there was an after-action report on Europe in the Dark Ages, the blame would have been placed on poor communications.  I wonder when we’ll stop using this centuries old excuse for problems that occur during disasters.

Communicating ideas can take place in many ways.  It can be voice, data, images, sounds, video and any other form of medium that you can image.  Using all these methods can still be challenging when all infrastructure is at its best.  Think of all the people who everyday complain about dropped cellular calls, emails not getting  through, files too large to upload, and so on.

Disasters have a way of magnifying all cracks in technology, as well as socially, culturally, and economically.  Expecting the same level of pre-disaster services during the disaster or after is just not realistic.  The infrastructure is weakened, and the users’ demands are increasing.

When you are asked to provide communications during a disaster, you will not have the assets to bring everything back online at once.  Each communication medium will need to be prioritized and rank ordered.  There is one place where the PACE acronym will come in.  Using PACE while writing your preparedness plans will also help set expectations across all the users.  Solid expectation setting is key to being successful during a disaster as everyone will be on the same thought process in evaluating your work.


Keep it simple.  People will use what they use every day to make communications occur.  Training is critical.  Ask a law-enforcement officer how much weapons training they have, and how much radio training they have.  Then ask which one they use more.  A common response that I hear is no radio training but it is used every day.  That’s a problem.

Locations and Connection Methods

There are many different types of sites that will need connectivity.  Fundamentally, they are all going to be the same.  Each site will need connectivity external to the site, such as to the Internet.  Each site will need some way for users to use the technology inside the site, such as a computer or phone.  Then these need to be connected together; a network or antenna wire.

All these systems will require a few basics to get started: space and power.  Do you have the space to bring these systems into the site, set them up and operate?  Do you have the power to bring the equipment online?  Secondarily, is there infrastructure to support the people: food, water, sleep, toilets, etc.

The “last mile” connections are going to be the hardest to finish in a disaster.  The core of the major utilities may be functioning fine.  The power station is generating electricity and it is getting to the sub stations.  The natural gas lines are charged.  The telecommunications network is active.  Except for where you are.  Include in your plans how you will overcome these challenges.  It will likely be a combination of direct work with the utility companies to be on the priority restoration list, and rental companies that can provide the service on an emergency temporary basis.

Wired communications

A single voice line is the basic unit of the phone system.  To you, this is both a pair of wires coming into your home plus a phone number.  These are really two separate things.  The voice line is the dial tone to your home.  The phone number is how the phone company identifies your line.  Business lines commonly have different numbers of voice lines and phone numbers.

I have a phone system with just under 2,000 direct dial phone numbers but only capable of just under 200 concurrent external phone calls.  Why?  Because all 2,000 phone numbers won’t be in use at the same time.  It is a lot like a gym membership.  They don’t expect everyone to show up on the same day to use the same treadmill.  Some use it in the morning, some in the evenings, and some never.  Some of my users will only be calling others in the same phone system.  These never use an external voice line and stay completely within the system.

Data lines are all based on the simple single voice line.  A single voice line can carry 64 kbit/sec, although the 8 kbit/s overhead make the practical maximum only 56 kbit/s.  A T1 circuit is also called a DS-1 or PRI.  The name varies depending on the specific use and those in the industry will be very specific.  For our purposes here, they are lumped together.  A T1 circuit is a bundle of 24 voice lines.  The math is simply 64 kbit/sec x 24 lines = 1.5 Mbit/sec.  A T3 circuit is a larger bundle and has 672 lines, therefore 43 Mbit/sec.  It used to be that a T1 was the gold standard for a circuit into a facility.  In my experience, a T1 can support 100 active users at best.  We’re now planning in the direction to pull T3s into large sites.  The sad part is that my home broadband runs faster than 4 Mbit/sec – almost three times the speed of a T1.


Additional resources