Jason Palmer, CPA, CITP

Cyber Insurance Auditing

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A brief refresher in Traditional Analog and Digital Voice Telephony

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Bell System Logo

Bell System Logo

If you have a telephone company provided wall jack for each individual phone line in your home or office, you probably have POTS – Plain Old Telephone Service – an affectionate name for traditional Analog copper phone line service.    This is a physical pair of copper wires that are directly connected between your home or office and the Telephone Company Central Office.  Each pair of copper wires from the Telephone Company provides an individual dial tone and phone number for your Telephone.

Traditionally, it is the responsibility of the Telephone Company Central Office to provide dial tone, line voltage, and ring voltage to that copper pair – the power that makes the phone work.  As many of us remember in the days before the Internet, even if the Utility Power was out, we could still make and receive phone calls.  Telephone sets had mechanical or electronic bells completely powered by the electricity provided from the Telephone Company Central Office.

If you have a larger organization with dozens of telephones and each person has their own direct dial telephone number and/or dedicated extension, you probably have a PBX (Private Branch Exchange – On-Premise Telephone Switch or Phone System) in a closet with one or more Primary Rate Interface (PRI) Digital Circuits from the Telephone Company.   Each PRI is capable of providing up to 23 simultaneous voice conversations.  A PRI is a special type of copper wire circuit, again between the Telephone Company Central Office and your Office.

Unlike the Analog POTS circuit described above, where there is a one to one relationship between the pair of copper and a telephone number, with a PRI, a virtually unlimited quantity of telephone numbers can be supported but only 23 simultaneous voice conversations can occur at one time per PRI circuit.

In either case, the similarities are that there is very long copper wire between the Telephone Company and your home or office.

If you have Telephone Service from a Cable company, you have a hybrid service that is a combination of both Digital and Analog services.  The “long copper wire” described above is replaced by a digital VoIP (Voice Over IP) service provided through a Cable Modem.

VoIP is a fancy term for delivering traditional telephone services over an IP Data Network, in this context, the Internet.

The VoIP service connects back to the Cable Company Telephone Central Office over the same Coaxial Cable that carries your television service.  Your existing telephone plugs in to an ATA (Analog Telephone Adapter – usually built in to the Cable Modem) that converts the digital VoIP data in to the traditional Analog, two wire pair that your telephone can use.

If you have Telephone Service from Verizon FiOS, you have a hybrid service that is also a combination of both Digital and Analog services similar to that which is provided by the Cable Company.  The difference is that the digital VoIP (Voice Over IP) service travels through a Fiber Optic Cable as laser pulsed light, instead of as electrical signals through Coaxial Cable, back to the Verizon Telephone Central Office.  Your existing telephone plugs in to an ATA (Analog Telephone Adapter) that is built in to an ONT – Optical Network Transmission unit.  The ONT is a specialized piece of equipment that converts the laser pulsed light in the Fiber Optic cable to an electrical signal that the ATA can use to provide dial-tone and a telephone number to your single line telephone.

The Telephony infrastructure is changing at a rapid pace.   It is now extremely rare to have an actual single pair of copper wire connected between your home or office and a Telephone Central Office five or twenty five miles away.  From the beginning of telephone service as we know it dating back over a century, this was common practice and exactly how the original AT&T Telephone Network was built.

In the examples above, Verizon FiOS is converting the Analog electrical signal that your telephone needs to a Digital Light Pulse inside the ONT installed in your home or office.   In essence, Verizon has replaced the miles of traditional copper wire with a Fiber Optic Cable directly connecting your home or office to the Verizon Telephone Central Office.

In areas where Verizon cannot bring Fiber Cable directly to your home or office, they replace the hundreds of pairs and miles of copper wire with Fiber Optic Cable to Junction Boxes in each neighborhood.  (One Fiber Optic Cable can replace hundreds or even thousands of copper pairs of wires.)  In each Junction Box is a monster size ONT that does exactly the same thing as the one used in the Verizon FiOS installation in your home or office above:  It converts the Analog Electrical Signals for the hundreds of pairs of copper wires that run from the Junction Box to your home or office in to pulses of light that travel over the Fiber Optic Cable back to the Verizon Central Telephone Office.

Hurricane Tech – Powering your Land Line Phone Service

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In the old days, Telephone Service was provided by a pair of copper wires that were directly connected between your home or office and the Telephone Company Central Office.  It was the responsibility of the Telephone Company Central Office to provide dial-tone, line voltage, and ring voltage to that copper pair – the power that made the phone work.  As many of us remember in the days before the Internet, even if the Utility Power was out, we could still make and receive phone calls.  Telephone sets had mechanical bells completely powered by the electricity provided from the Telephone Company Central Office.

Fast forward to the modern day and the POTS line (Plain Old Telephone Service – an affectionate name for traditional copper phone line service) is fast becoming extinct.  Cable companies are moving customers away from traditional analog copper and over to digital VoIP (Voice Over IP) services provided through a Cable Modem.  Voice is now a digital data service and an ATA (Analog Telephone Adapter – usually built in to the Cable Modem) converts that digital data in to the same two wire pair that your telephone can use.

As Cable companies convince you to give up your “almost guaranteed to work in a power outage POTS lines” they quietly tell you, “If you lose Utility Power, a battery in our Cable Modem will keep your phone working for between four and six hours.”  What they fail to remind you of is that if that Battery is not periodically checked to make sure it is properly charging and still functioning, when the Utility Power goes out, so will your telephone service.

To make matters worse, almost everyone uses either cordless or corded phone that has a base station that requires electricity to operate.  Even if the Battery in the Cable Modem is providing Dial-Tone, it is of no value if your Telephone requires Utility Power to operate.

It is a catastrophe waiting to happen.  For those of you thinking, “Well I will just use my cell phone.”  In a severe storm, especially if Utility Power is off in the area, it will only be a matter of time before the Cell Towers lose power and exhaust their backup power sources and shut-down as well.  Even if the Cell Towers remain operational, your Cell Phone Battery will eventually run down.

Solution:  Proper Planning.

First – If you have your Telephone Service through a Cable Company, make sure that your Cable Modem, which usually provides your Telephone Service, has the “Power Failure Battery” installed.  If your Cable Modem provides Telephone Service and does NOT have a built in Battery Backup, ask the Cable Company to exchange out your equipment for a model that does have a Built-in Battery Backup. Note: Some Cable Companies provide a free UPS in place of a Built-in Battery Backup for the Cable Modem.

Second – If your Cable Modem already has a Built-in Battery Backup, make sure you check it at least once a month to verify that the Built-in Battery Backup is properly charging and functioning.  If you are not sure how to verify the health of the Battery, ask your Cable Company. Usually there will be a series of lights: Charging, On-Battery, and Replace Battery.

Third – Make sure you have a traditional Line Powered Telephone.  A Line Powered Telephone is one that does NOT have an electrical plug – only an RJ11 telephone “silver satin” cord that plugs in to the wall jack. It is O.K. if the phone takes batteries for functions like Caller ID.  NOTE:  Some phones that do require Utility Power A/C electricity have a “Power Failure” mode where even though the ringer may not ring, you can still pick-up the receiver and make an outbound telephone call.  This is not optimal but acceptable for being able to dial 911 for an emergency.

Fourth – As an alternative to the Built-in Battery for the Cable Modem and a Line Powered Telephone, you can purchase a decent size Uninterruptable Power Supply (UPS) Battery Backup Unit.  The higher the Wattage, the longer the unit will power your Cable Modem and Telephone Base Station – both of which have electrical plugs which can be connected directly to the UPS.  This may be an expensive option in that a 1500 Watt rated unit, which can power the above situation for four to six hours, can cost upwards of $200.  This also assumes that your Telephone and your Cable modem are in close proximity and can both reach the UPS to be plugged in.

In summary, if you do not have the luxury of having both Traditional POTS lines, that will work without Utility Power, and VoIP lines, then make sure you are able to provide some kind of Power (Internal Battery or UPS) to both your Cable Modem and to your Telephone to keep your VoIP service working.