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Why Splits Are Preferable To Overlays

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  policy telecom

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How many digits constitute a telephone number?

The most common answers, at least in the United States, which is part of the North American Numbering Plan (NANP), are 7 and 10. There's a pretty good chance that whatever answer YOU gave says something about your age.

For the record, telephone numbers are 7 digits long. They have been since 1947 when AT&T devised the NANP, in which area codes, officially called Numbering Plan Areas (NPAs) played a prominent role. It's why you write area codes in parentheses (unless you don't know how to write telephone numbers correctly). The NANP unified the Bell System in an era when there were no real standards for telephone numbers. Some communities dialed 6 digits, others dialed 5 — still smaller communities dialed 4 digits. Other communities dialed no digits at all, and had to wait for an operator to come on the line when they picked up. Apart from instituting area codes, the NANP standardized telephone numbers at 7 digits in length.

In practice, not everyone had to dial 7 digits right away. In an era of completely electromechanical telephone switches, particularly step-by-step (SxS) with its digit-absorbing selectors, which allowed for greater flexibility in dialing plans, customers were often able to dial less than 7 digits for years, even decades after the NANP went into effect. Today, virtually everyone must dial at least 7 digits to make any telephone call, unless you happen to behind a PABX (Private Automatic Branch Exchange), in which case the usual standard is 4 digits.

Back to my original question. I said I could predict your age based off of your answer. If you answered correctly, that is, if you said 7 digits, then hats off to you! If you answered 10 digits, don't be too hard on yourself — you were probably born after the Cold War ended, in which case you have been all too familiar with area codes all your life, even when you probably shouldn't have been.

The decision about splits and overlays recently occurred to me to be a rather contentious and divisive one. Most people may not even know what I'm referring to when I mention splits and overlays, but a telephone hobbyist or telecom worker will instantly, and may even cringe or grimace at the thought. But the rest of you may ask: what is a split? What is an overlay?

Splits and overlays are the principal "solutions" to NPA exhaustion, otherwise known as area code relief. It's no secret that there are far more than just telephones plugged into the wall as there were when the Bell System adopted the NANP. We now have modems, fax machines, alarm systems, ATMs, cash registers, and many other novel contraptions today that have become mainstream in the years following the development of the NANP. That's not even to mention the array of things that don't plug into a wall at all: namely VoIP (Voice over Internet Protocol) phone numbers, which are not tied to anywhere in particular, and mobiles — or cellular phones — which all have their own unique phone number, despite being computers more so than telephones (albeit very crude ones).

At the time, the only expected growth factor in the use of telephone numbers was a rise in the human population itself. More people meant more households and families, each with their own telephone number. But today, with a dizzying amount of things, physical and virtual, that demand phone numbers in much the same way computers demand IP addresses, we are running out of numbers faster than ever.

Well, technically, perhaps, that's not quite right. To understand why, you need to know a thing or two about how the NANP works.

Without getting too technical, the NANP standardized area codes and telephone numbers to have the following format:


NPA represents the Numbering Plan Area, or "area code" as the laymen say. NXX is the local exchange, and XXXX is the station number. Generally, all the numbers in a local exchange are operated by the same company, though in recent years, number pooling is sometimes done in blocks of 1,000 instead of blocks of 10,000. And therein is the problem.

Well, the second problem actually. The first problem was the Bell System Divestiture, which, among other things, like permanently ruining the world's best telephone network, opened the door to competition (an economist's favorite word) by eliminating monopoly (an economist's least favorite word). With the misguided belief that monopoly is always bad and competition is always good, the United States Justice Department opened the door for more telephone companies to enter the arena. To be fair, independent companies existed during the Bell System's reign, from 1899 until the end of 1983 — the largest of these independent companies was GTE (General Telephone & Electric, later General Telephone & Electronics). But they never existed in the scope that they do today; now, there are a dizzying number of telephone service providers all over the country.

That brings us to the second problem: blocks of 10,000. When a new telephone service provider is allocated new telephone numbers, it doesn't get just one number. It doesn't get ten or one hundred: it gets ten thousand. Now, back when there were relatively few telephone companies, this wasn't as big of a deal. But now, many small telephone companies that may not even use half (or even a tenth!) of their allocated numbers, are still allocated blocks of 10,000. Slowly, this is changing, in some cases. But by and large, this remains the case. With many small telephone companies each claiming huge pools of numbers, many of which are never fully used, our number pooling system begins to fail us. Neal McLain said it better than I can:
During the late 1990s, when it was not possible to break up 10,000-number blocks, every new entrant got a separate NXX code. Even though it may not have needed anywhere near 10,000 numbers, it still got 10,000 because that’s the way the system worked. — McLain, 2009, pg. 10

So: competition + number pooling by the 10,000. Not a healthy combination when the number of gadgets and gizmos is already spiraling out of control. Add in the fact that numbers are sadly becoming more associated with people rather than places (as they were meant to be) and Generation Z's expectations of one number per person rather than per household and the NANP has a stomachache.

In this case, the primary medicines used are splits and overlays, but they both have very different effects. It is important to realize what the problem actually is, to begin with. Once again, I'll turn to Neal McLain:

...the problem: area codes don’t run out of telephone numbers; they run out of NXX codes. — McLain, 2009, pg. 10

Understanding that is crucial. Hundreds of thousands, perhaps millions, of telephone numbers, may be unused at the moment. Who knows? The NANPA (North American Numbering Plan Association) has no way of knowing. Each individual telephone company may not even be sure of their exact usage, let alone the whole system at large. What the NANPA does know is that NXX codes are running out, fast, in almost every NPA. And that's a problem, because that's how numbers are allocated to telephone service providers, and then to you.

More NXX codes cannot simply be created. Because of restrictions regarding valid NXX codes (which I won't cover here for the sake of brevity, but you can read more about them here), there are a limited number available in each NPA. Once an area code is exhausted, the only solution is (gasp!) an entirely new area code!

How to make the new area code? That's where splits and overlays come in. An overlay is when the new area code is simply implemented in the same geographic area as the old area code that has been exhausted. A split is when the exhausted area code's geographic area is split between the older area code and the new area code. Half the numbers then get transferred to the new area code, allowing for further growth in both the older area code and the new one. So, which solution is better?

As indicated by the title, I'm a firm believer in splits, rather than overlays. Each has its inconveniences, but I believe that the impacts of one far outweight the other. The big problem with splits is that half the residents in the exhausted area code suddenly find themselves in a new area code. For most households, this shouldn't be a huge issue. What belongs to you, but others use it more than you? Your name. Likewise, your area code is not really relevant to you — it's really only relevant to people who are trying to reach you from other area codes — more or less, people who are calling you long-distance (though even that line has blurred these days). Businesses, as you might expect, often conduct a lot of business with clients from distant places, sometimes across the country. For this reason, their literature often includes their area code for convenience. Initially, the Bell System published little blue booklets that had a list of cities and their corresponding area codes. Today, this has been integrated into the print version of the telephone directory (the Yellow Pages and the White Pages) and often appears as a map as well as a listing by area code and a listing by state and city. If you know your grandma lives in Seattle, you can simply look up the area code, find it to be 206, and then dial 1+206, followed by your grandma's Seattle telephone number. But if you do frequent business with a company, you certainly aren't going to do that. You'll look up the number once (or more likely, you'll receive it printed on a business's contact information for your convenience) and simply keep using that area code when you dial.

Back in the day, area codes weren't as well-recognized as they are today. Certainly, they weren't mainstream or popularized, and nobody ever dialed 10 digits for a local call as many mistakenly do today for no reason at all. When an area code was changed for a region (which itself was much rarer an occurrence than it is now), the number was changed in the telephone company's literature, and when you received your new telephone directory and your new area code booklet, you would find them updated with the latest information. Possibly, you may never even remember that there was another area code previously.

Whereas the format for giving your number to people in distant places used to be the number in conjunction with your city, it has now become your area code in conjunction with your city. Your current area code, I should say. Because if your area code changes, your pal suddenly is unable to reach you, whereas if your location changes, your number would have to change anyways. Telephone numbers, simply speaking, were better tied down to a specific location than a specific area code, because their area code could change but their location never did.

Well, the Bell System solved this problem anyways. When area codes were changed, customers dialing the numbers in the old area code received a message much like "The area code for the number you dialed has been changed to 253. Please redial using area code 253.

Failing that, an operator would come on the line and assist you with whatever trouble you were having. Soon, you would be connected to Aunt Mabel, and the next time, you would dial directly using the correct area code and forget entirely about the old one.

Well, today, a great number of calls are not made from real telephones anymore, in which case if you misdial, you may get a recording, but you certainly won't be able to get an operator on the line to help you. Furthermore, the idea of looking up area codes in a booklet or directory has more or less fallen by the wayside. Just this past Friday, my fingers were scanning the pages of a phone book, surveying the listings of area codes. But I am probably in the minority on that count, and the directory happened to be from 2007, meaning that if an area code did change, the new one would not be reflected in the directory. Phone book replacement is another thing that is no longer as common or frequent as it once was. As fewer directories are published farther apart, there's a much greater chance that households and businesses will be using the old information.

Consequently, when an area code changes, this can wreak havoc, particularly if a caller is not even familiar with the exact location of the party he is trying to reach. Thankfully, intercept messages usually solve this problem, like they did back then, but that's not always the case.

If this is such a problem, why are splits still the way to go?

When an overlay is implemented, that means two or more area codes coexist in the same geographic area. Walking down the street, there would be no way to say for sure which area code the telephone numbers on that block were in. Instead of just giving out your number to your friends, you would need to give out your area code as well. Of course, many young people already do this redundantly anyways since they don't understand the difference between 10 digits and 7 digits, but imagine if it was mandatory!

This is only the tip of the iceberg. The FCC settled on something called "dialing parity" back in the late 1990s. What this means is that whenever an overlay is implemented, you must not only dial the telephone number but you must also preface every call you make with its area code.

There is no technical reason for this. In theory, standard 7-digit dialing of telephone numbers could remain even when an overlay is implemented. You might still have to dial 10-digits half the time if half the people you know are in the new area code and you're in the old one, or vice versa, but at least you would be able to dial just the telephone number itself to reach people in the same NPA.

Well, the FCC decided this wasn't fair, again, with "anti-competitive rhetoric". The following Q&A from South Carolina summarizes the decision perfectly:

Ten-digit dialing is a regulatory requirement established for an overlay area code by the FCC in its Second Report and Order (FCC 96-333). Its purpose is 1) to mitigate any anti-competitive effects that would unfairly advantage incumbent providers and disadvantage new providers and their customers and 2) to ensure dialing parity between the two area codes. This dialing requirement results from a concern that customers in the original area code and customers with the overlay area code would have different dialing arrangements for the same geographic area. Those in the original area code could reach a party in their same geographic area with a seven-digit call, while those in the overlay area code would have to dial 10 digits to reach the same party.

In other words, everyone in the overlay needs to be able to dial any other party in the overlay in the same way, regardless of area code. Hence, everyone in the overlay loses the ability to dial calls using just the telephone number. You must dial the area code plus the phone number, even when making calls within your own area code that are not long-distance. To most people, this is extremely bizarre and unintuitive, though I suppose babies who were born with mobile phones in their cribs are already conditioned to (usually erroneously) dialing 10 digits all the time anyways, even though usually the required number of digits is 7 (local) or 11 (long-distance), but never 10, unless you live in an overlaid area.

Overlays have been gaining ground in the past two decades. According to a NANPA report regarding all the new NPAs introduced in the past 10 years, 63 of the 75 area codes introduced in the past decade have been overlays, as opposed to splits. If you look at the NANPA's page of proposed NPAs that are not yet in service, every single one of the proposed NPAs is an overlay. Every single one. Whereas it used to be that every new area code was a split, the de facto these days is now an overlay.

I should here reiterate the inconvenience caused by splits and overlays. With a split, your area code might change. Notice I said, might. You could end up lucky and live in the part that is sticking with the original area code. In metropolitan areas, this is usually the downtown area or main hub of the geographic area, usually the most densely populated areas.

Regardless of whether your area code changes, your number itself will not change. With an overlay, neither your area code nor your number will change, but you will have to dial 10 digits. When a split occurs, each area code is assigned to a geographically separate area and so regular dialing of calls can continue... at least until the new NPAs are exhausted, in which case you had better hope another split occurs, because an overlay would put you back in the same boat.

In other words, the inconvenience caused by a split is generally temporary. Business cards may need to be updated if a company has clients in distant places and published its area code on its literature. Aunt Mabel may get a wrong number once, have to consult her directory or the operator (that is, if no intercept message corrects her first), and then dial again. But after a while, people move on. Soon, people may feel as if they have always lived within that area code, even if it is the new one.

Case in point: the 262 area code. 262 was split from 414 in 1999. Just three years earlier, 920 was split from 414. The Public Service Commission was in charge of the decision to do an overlay or a split. In the end, they voted 2-1 to do a split. This is why, thankfully, I am able to pick up the phone and still dial 7 digits, instead of 10. On a rotary phone, you know, that can be quite the nuisance!

Was a split the right decision? Did anyone become adversely affected by the split? Well, I grew up never knowing that 262 territory was once 414 territory. Only recently when consulting old telephone directory information did I become aware that some 262 office codes were once 414 office codes, which meant that at one point they were part of the 414 area code. It's now been nearly 19 years since the new area code went into affect, and virtually nobody even gives any thought to 262. Of course, those who are old enough to remember may recollect that the area code at one point was indeed 414. But that's not something they would likely think about when they pick up their receiver and make a call. On the other hand, if an overlay had taken affect, you can definitely bet that a large number of people would be cursing the phone company, the FCC, and whomever else they could curse as they subservently dial 10 digits.

In a recent discussion on a telecom listserv, I seemed to be in the minority of those who favored splits over overlays. But if you consider the general population at large, that's not necessarily the case. Here's another helpful statistic from Neal McLain, this time from his 1999 write-up about the 262 split from 414:

According to the PSC, the public favored a geographic split. Surveys published in its recent order show that 60% to 70% of residential customers prefer a split, primarily to retain 7-digit dialing. These same surveys also show that an even higher percentage of businesses prefer a split — this in spite of the fact that many of them would have to change area codes. — McLain, 1999, pg. 4

60% to 70% of people favor splits over overlays. Of course, this statistic is almost twenty years old now, but I highly doubt that public sentiments about splits and overlays can have changed that much in the interim. Many more people may have gotten used to dial 10 digits, either out of ignorance or necessity, in the meantime, but the vast majority of us relish being able to dial just the phone number, no area code nonsense, when making a local call.

And what's this about businesses favoring splits even more highly than consumers, despite having to change their printed literature? Clearly, the verdict is favor of the split, right?

The article goes on to say that since the late 1990s, the telecom industry at large has favored overlays more than splits, when originally it favored splits over overlays. Why exactly is not necessarily clear, but the NANPA has adopted their thinking. Virtually all new area codes are now overlays, and "In the years since 1999, overlays have become widespread, and now cover over half of the population of the United States." (McLain, 2009, pg. 3).

There are more subtle arguments for both cases as well, many of which were quoted in the recent listserv conversation. One comment was "making splits requires predicting which parts will grow faster, and which slower. Otherwise you soon split again". That is perfectly true, although if an overlay were implemented instead, a third overlay could become necessary as well at some point.

Another argument was that "with a split, the border is often politically contentious". When 262 split from 414, the border was more or less the Milwaukee County border, but this was perhaps one of the easier cases. Area code splits often follow seemingly meaningless boundaries. The NXX codes must be taken into consideration, to ensure that the central office codes themselves do not get split between two area codes. And certainly, it may be all to easy to relegate the "marginalized" parts of cities to the new area code when it is split, leaving the more affluent parts in the original area code.

Yet, overlays are hardly less riddled with problems. Apparently, four places in North America now have not two, not three, but four coexisting area codes! New York City, metropolitan Atlanta, metropolitan Houston, and the entire Canadian province of British Columbia have 4 area codes in the same geographic area. Can you imagine living in such a place? Take Houston for example. Bill is in area code 713, the original area code. Betty is in 281, and Sally is in 346. You are in 832. Good luck keeping up with all of that. You could all live on the same street, and be in four separate area codes. All nonsense that could have been easily averted if Houston had opted for a split instead of an overlay.

The truth is that when area codes are split, the inconvenience is temporary. When area codes are overlaid, the inconvenience is permanent. If the area where you live is ever overlaid (or has already been overlaid, which is quite likely considering that more than half the U.S. has now been overlaid), then you will have to dial 10 digits for every call you make, until you die, or move. You will never again be able to dial 7 digits to make a local call. Ever. Again. Yes, you could buy expensive telephone equipment that would prepend the required digits to the beginning of every call, but that would require extensive dial plan configuration and annoyance that the average consumer is not going to do (and furthermore, calls from any other phone would still require 10 digits). Today, in 262 land, hardly anybody thinks about it once being 414 land, if they remember at all. The inconvenience came and went. I mentioned that the decision to split 262 from 414 was a 2-1 decision. If the vote had tipped the other way, and 262 had been an overlay, two decades later, we would still be putting up with its inconveniences.

Something to keep in mind is that, as mentioned in the listserv discussion, splits may often beget more more splits later. Although the first overlay in an area is always extremely painful, subsequent overlays are not as difficult, since everybody would have to dial 10 digits already whether or not that new area code was overlaid. Although keeping track of 4 coexisting area codes sounds like a real hassle, millions of people do it everyday. I'm sure automatic dialers and speed dial have done something to eliminate some of the inconvenience, but the inconvenience will always linger and never quite go away.

Still, I would rather live through multiple splits than a single overlay. No matter how many splits happen, a couple years after the last one, nobody will give any thought to the changes. Everyone will have adjusted. On the other hand, a single overlay will disrupt life in that area as people knew it forevermore.

The annoyance of dialing parity is not the only reason overlays are a pain. In the end, we circle back to semantics and the Bell System's intentions. The idea of an area code, or NPA as it was officially known back then, was that each area code would uniquely identify a specific geographic area code. While splits maintain that tradition, overlays do not. Bill in 713 and Betty in 281 may be neighbors, but you would never think that if they gave you their telephone numbers prefaced by their area codes. At its foundation, the very concept of an area code was devised around the notion that each geographic area would have its own unique area code, and this requires that every geographic area be identified by one area code, and one area code only. In an overlaid area, it's impossible to stop someone on the street and ask "So, what's the area code around here?" If you want a single answer, you won't get it. If you're in Houston, he'll have to tell you 713, 281, 346, and 832, and now all the mental exertion that could have gone into many of the numerous millions of more productive tasks will now go into mentally wrapping your head around this bizarre setup and trying to keep track of it.

A great many places in North America, including most of Canada, now require 10-digit dialing. You can view the full list of area codes that do on the NANPA's website, although you probably already know if you're required to dial 10 digits or not. Here in 262, we can keep dialing 7 digits for the forseeable future. According to NANPA's most recent projections on when each area code will be exhausted, 262 will survive without "relief" until 2045. A search for 406, however, home to the future me, yields a much grimmer result: Montana's original and only area code since 1947 is due to be exhausted in 2029. It may be a long shot to hope that 406 will be split instead of overlaid when the time comes for 406 to be relieved, but I'll be praying for it anyways.

If you still support overlays, for whatever convoluted reason, this satirical video sums up the situation nicely.

The following resources were of immense help in constructing this article:

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