You’ve heard of child prodigies who can play Mozart on piano or perform calculus at the age of 5.

That wasn’t me.

I did, though, memorize my home telephone number: Wabash-1265.

Actually, it boiled down to W-1265. Only the first letter of the local prefix names — officially known as “exchanges” — was dialed in greater Terre Haute in the mid-1960s. “W” for Wabash, “C” for Crawford, “H” for Harrison, and so on, with each exchange representing a different geographic sector of the community. A “W” translated to a 9, “C” a 2, and “H” a 4, according to the letters-to-numbers format on a rotary telephone.

So, if a kindergarten classmate needed to call me, he would spin 9-1265 in sequence on the phone dial. (Probably concerning bike riding or a kick-the-can game, rather than a concerto or algorithms.)

All of that seems quaint in 2013 … rotary phones, exchange names, 5-digit numbers, one-phone households.

We’ve come a long way, baby.

“Dialing” amounts to tapping your finger on a touch screen. “Prefixes” switched from exchange names to 3 digits after 1966, locally. “Phones” no longer have cords, fit in the palm of your hand, connect to the World Wide Web, and transmit text messages, photos and hilarious slogan posters to any and all of your 768 Facebook “friends.” A family of four may have seven phones — personal cells for parents and kids, a landline, and work mobiles for Mom and Dad — and, thus, seven phone numbers. Maybe eight, if they’ve got a home fax machine.

So, it’s hardly a shock that southern Indiana is on the brink of using up every possible 7-digit phone number in its venerable 812 area code. The Indiana Utility Regulatory Commission discussed a handful of options for “area code relief” last week in a public meeting at Terre Haute — one of several IURC sessions planned in the 812 region, which covers the lower-third of the state. A decision must be in place by 2015. The likely choice is an “overlay,” which allows anyone with an existing 812 phone number before 2015 to keep it, and phone numbers issued after the overlay would have a new area code. The other possibility is a geographic “split,” a physical division of southern Indiana into 812 and a new area code.

On the upside, the overlay would spare businesses the expense of changing numbers; on the downside, every local call would require dialing all 10 digits, area code and all. And, next-door neighbors could have different area codes.

The real surprise is that this situation — “area code exhaustion” — took so long to occur.

Of the original 87 area codes created by AT&T and Bell Laboratories in 1947 across the nation, 812 is one of a small number that hasn’t maxed out the pool of 7-digit numbers and remains intact. “There are not that many that have” remained intact, said Wayne Milby, senior area code relief planner for the North American Numbering Plan Administrator, a neutral overseer of the continent-wide system.

In Indiana, northern Indiana (once 219) split into 574, 260 and 219 in 2002. Central Indiana (once 317) split into 765 and 317 in 1997. Nationwide, since 1995, the number of area codes has doubled.

Maybe other regions gobbled up new technological devices faster than 812. With just 22 percent of the state’s residents, maybe the southern Indiana population generated less demand than other locales. Maybe generous allocation of three area codes for Indiana in the original mapping in 1947 — most states received just one, Milby said — eased the strain on 812 numbers.

Regardless, we are about to shove the days of “Wabash-1265” ever deeper into the past.

The numbers involved in this technological saturation stagger the minds of folks who’ve actually placed a forefinger in the rotary phone dial or asked an operator to place a long-distance call.

Each area code contains 7.92 million useable 7-digit phone numbers. The population in the 812 region is approximately 1.4 million people. Together, we’ve used up all but 500,000 of the eligible phone numbers, according to IURC projections. The proliferation of tech gadgets such as pagers, faxes and cellphones rapidly drained the well of numbers. In 2001, phone numbers issued to telecommunications providers in blocks of 10,000 were trimmed to blocks of 1,000, which reduced the amount of idle unused numbers and bought 812 an extra decade of life as-is.

“As-is” doesn’t last long in the 21st century, of course.

“It’s amazing how quickly this technology has changed,” said John Koppin, president of Indiana Telecommunications Association for the past 28 years.

Like many baby boomers, Koppin can instantly recall his childhood phone number in Indianapolis, “Clifford-54527.” (Given its size, metro Indy needed an extra digit.) Nostalgic as that sounds, dialing a “C” and 5 digits marked a huge advance from the early days of asking an operator for a connection to a number. A Hoosier undertaker, Almon Strowger of LaPorte invented the mechanism, enabling customers to dial themselves after he figured out a local operator was routing people needing funeral services to her husband, a rival undertaker, Koppin explained.

From that breakthrough came exchanges such as Wabash and Crawford, area codes and the current 10-digit phone numbers.

Those 10 digits will come in handy. The number of mobile phones in use in the U.S. — 327 million — exceeds the population. The concept of carrying my own phone in my back pocket would’ve seemed so “Star Trek” back when I was memorizing Wabash-1265 and our lone family telephone — a sturdy, curly-corded, beige Model 500 — sat on the countertop in our kitchen.

Despite the spread of devices and the need for numbers, the FCC and NANPA say there are enough potential area codes (792) and 7-digit numbers (7.92 million per area code) to last until 2042, or beyond. Less than half of available numbers are in use, said Mark Wigfield, FCC spokesman. Just in case, an FCC task force — the Future of Numbering Working Group — is tracking trends to give the commission ample time to avert a shortage.

Post 2042, what happens? Climbing to 11 digits from 10 would expand the possible phone numbers by tenfold, Milby said. It would also cause a Y2K-style uproar in terms of programming the tech gadgets.

In the meantime, southern Hoosiers must get accustomed to a different area code and some extra local dialing. The new area code cannot be made public until NANPA receives the relief order from Indiana, Milby said. But the numbering guidelines for area codes narrow the possibilities — it can’t match any of the 3-digit prefixes now in use in 812; the first digit can’t be a 0 or a 1; and, preferably, it won’t be too similar to other Indiana area codes or those in bordering states.

So, Bond fans can’t lobby for 007. And 666 — still unclaimed — is probably out, too.

Otherwise, plenty of mathematical possibilities remain in a numbers pool still 30 years deep. Somebody get a prodigy on the phone to figure it out.

Mark Bennett writes for the Terre Haute Tribune-Star.

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