Andy Larsen: How did Utah get its 801 area code? Why additional ones? And will more be coming?

Our data columnist dials in on the history and reasoning behind the numbers we use every day.

(Francisco Kjolseth | The Salt Lake Tribune) Former Secretary of the Navy Ray Mabus, right, is joined by former Utah Gov. Gary Herbert after the announcement of the nuclear submarine USS Utah (SSN 801) at the Utah Capitol in 2017. Virginia-class submarines are typically named for states, and the Navy had been waiting to name the submarine whose registry number is to be 801, the telephone code for Salt Lake City and most of the Wasatch Front.

801 is an identity.

Right now, you can buy all sorts of 801-branded gear: T-shirts, hoodies, bumper stickers, phone cases, hats, you name it. Companies from 801 Accounting to 801 Web Design have chosen the number to represent their businesses. Uinta Brewing’s 801 pilsner beer is one of the bestselling beers in the state. All of this is because many, but not all, Wasatch Front residents have phone numbers beginning with 801, and somehow, those three numbers tie back to home.

So I decided to look into area codes as a phenomenon. How did Utah end up with the 801 area code in the first place? Why does Utah now have three area codes, including 385 and 435? Couldn’t they just fit all of Utah’s 3.3 million residents into one code? And what’s the future for Utah’s area codes? Could we be adding another anytime soon?

The area code story

In the 1940s, AT&T realized it had a problem. It was sitting at the top of an empire of most of the phones in North America, but they all had grown out of these local and regional organizing groups, which meant that each had its own numbering schemes. Human phone operators were a necessity for long-distance calls from both a technical and a logistical standpoint.

In particular, most U.S. cities had an automatic central switching office with a capacity of 10,000 numbers. In cities with more than 10,000 lines, customers would dial two letters — yes, letters — to indicate which switching office they wanted to reach, then their desired answerer’s five numbers. For example, The Salt Lake Tribune’s phone number in the time period was EM-31511.

AT&T wanted to make it possible to unify these regional numbering schemes. The obvious answer was to add more digits in front of customers’ existing numbers when people wanted to dial outside of their familiar local area; these were called area codes. AT&T also included 20 North American countries in the numbering plan, which was later sensibly referred to as the North American Numbering Plan, or NANP. (Mexico and a few other smaller North American nations don’t participate in NANP.)

At first, human operators were the only ones familiar with the area codes, as kind of a back-end solution to the numbering problem. The first consumer-dialed long-distance call came in 1951, and the practice expanded throughout the ’50s to the point that direct dialing was the norm by the early 1960s.

When they were first introduced, there were 86 area codes — required by a combination of both the population and the quantity of numbering systems at the time. Naturally, population growth over time forced the introduction of new area codes, and there are now 447 assigned area codes in the NANP.

Why 801?

So how did we end up with good ol’ 801 here in Utah?

As AT&T administrators thought about how to make the system, they first considered the technical aspect. In particular, how do you ensure that area codes are recognized as such, and not part of a normal local number? Well, no two-letter phone local switching office includes a zero or 1. So they decided every initial area code had to include those numerals in the area code in the second number to ensure it wouldn’t be confused with a switching office. Second-number 1s were assigned to states that were split up, second-number zeros were assigned to states with just one area code.

They then considered efficiency. They noted that it would be most efficient to keep the first and third numbers as low as possible for as many people as possible. People were still using rotary phones to dial, and 8s and 9s took longer to dial than 2s and 3s. Therefore, it made sense to give higher-density cities, like New York, lower-digit area codes like 212.

They also figured it might help people remember the area codes if they were grouped geographically. This was the proposed map when administrators first laid out numbers in early 1947:

Document from Bell Labs internal history "Bell Labs, Memorandum 40979" (https://archive.org/details/keevers-1975-12-12-bell-labs-memorandum-40979-nanp-the-first-thirty-years/page/n10/mode/1up)

Ultimately, though, this proposal was rejected. Why? Well, for two reasons. First, a system like this might actually increase misdials, as people on the border of an area code district might not easily remember, say, the difference between 212 and 213. More importantly, it wasn’t as flexible for new growth. What if California’s population exploded, and the state needed dozens of area codes there quickly? Area codes with a 5 at beginning would run out.

So, in the end, officials distributed them with no real regard for geography. Utah got 801, a number with a large initial number but a small third number.

Original distribution of area codes. Note how effort was made to make the digits in area codes take as little time to dial as possible. (https://en.wikipedia.org/wiki/Original_North_American_area_codes)

Why did Utah have to expand out of 801?

This has always bothered me. Why do we need more area codes than 801, anyway? With seven trailing digits, there should be room for 9,999,999 numbers in each area code, right? That’s way more than the 3.3 million people who live in Utah.

There are three big reasons why.

• First, there aren’t 9,999,999 numbers available. Zeros and 1s aren’t allowed in the first digit of a seven-digit telephone number. And 211 through 911 numbers are reserved for services, and 555-0100 through 555-0199 are reserved for fictional numbers. In the end, each area code has 7,919,900 numbers available.

• Second, there are more numbers than people. Businesses have phone numbers. Some people still have home phone lines, fax machines, even pagers with their own number.

• Third, we assign phone numbers pretty inefficiently. Historically, local telephone companies dealt with blocks of 10,000 numbers at a time, all with the same three-digit prefix. They would assign a whole prefix to one largish company and call it good, whether that company wanted 2,000 numbers or 8,000. That got messy and wasteful, so, in 2002, the Federal Communications Commission said phone companies would have to distribute blocks of 1,000 numbers, with the same four-digit prefix instead. This smaller block process helps but still results in a decent amount of waste.

The most recent FCC report on the issue, from 2019′s data, showed that 69% of 801 area code numbers have been assigned. As of that report, traditional wireline phone companies are sitting on a whopping 1,593,000 numbers in the 801 area code, while mobile wireless carriers have 110,000 unassigned numbers. However, even if you were to distribute them all, the amount of unassigned numbers in 801 still doesn’t accommodate the state’s needs — hence the 435 and 385 area codes.

Why 385 and 435?

By the 1990s, the adoption of fax machines, pagers and so on forced NANP administrators to rapidly expand beyond the “zero or 1 in the second digit” rule. The first area codes outside that rule were assigned in 1995.

By 1996, it was clear that Utah would have to get a second area code soon. Two methods of area code expansion exist: the split separates the geographic boundaries of one ZIP code into two, while the overlay puts a second area code in the same boundaries as the first one. However, in 1997, the overlay method hadn’t been used yet, so the NANP administrators split Utah in two: Salt Lake, Davis, Morgan, Utah and Weber counties would all remain on 801, and the rest of the state would become 435.

Why 435? Well, state public service officials originally asked for the available area code 724 — recognizing Utah’s July 24 holiday. But the 801-724-XXXX block of numbers already were assigned to phones in Orem, and NANP administrators didn’t want to confuse the public in the 801 areas who might dial seven digits, nor the systems that would interpret those digits. Instead, the unassigned 435 was used.

“For us, area codes are buckets with numbers in them,” a NANP administration spokesman said when asked about the selection of 435. “It really is a boring, unromantic, practical piece of work that needs to be done.”

The area code 385 became necessary in 2009 but, by then, the overlay had become commonplace, so NANP administrators did that. It was assigned in a boring, unromantic, practical way as well.

Number growth has significantly slowed, thanks to the reduction of home phones, fax machines, pagers, etc. The 801 and 385 area codes are currently projected to get us through at least 2032, while 435 is projected to suffice until at least 2041.

Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at alarsen@sltrib.com.

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