Apple's iPhone 4S sold four million units in its first weekend of sales. But the entire rugged phone industry sells only half as many devices over the course of an entire year.

That's a good definition of niche market, according to figures from IDC, and one that's noticeably lacking in smartphones. We spoke with Sonim's CEO Bob Plaschke about his company's line of rugged phones, how the likes of Motorola and Samsung are trying to compete, and why we haven't seen a truly rugged smartphone—yet.

Cult following

Sonim has a made a nice living over the past few years selling ruggedized feature phones to users in security industries, oil and gas utilities, agriculture, and heavy manufacturing—fields where typical phones just won't cut it.

These people want a phone that can last an entire day outdoors without a power source; a screen they can still see outdoors; buttons or touch functionality that are responsive enough to be used with a glove; or a speaker that can ring incredibly loud.

"All those things you can't find in an Otterbox, you can't find in a case for iPhone," Plaschke says, attempting to dispel the notion that ruggedization is only about build quality and weatherproofing. Device protection is a big deal in the consumer market, but it's only half the battle as far as business users in the field are concerned.

Meeting spec

As we previously covered, ruggedized phones are often built to adhere to a number of industry standards for dust, water, and drop protection. The problem is that these protections require materials and construction that aren't found in your typical smartphone. This can pose a financial burden on manufacturers when the market for rugged phones is so small.

"We couldn't convince the large OEMs like Samsung or Motorola to build ruggedized phones for this class of folks," Plaschke says of years past. "They were willing to put some rubber on the phones, around the edges and make it waterproof, but they weren't willing to build to the specifications that these folks who work outdoors demand."

Of course, times have changed, and the likes of Samsung, Motorola, and even Casio are now making ruggedized smartphones that adhere to industry specs—with the promise of surviving low-temperatures and four-foot drops. But Plaschke feels there are still certain areas where smartphone ruggedness falls flat, at least when compared to the standards met by previous Sonim phones.

Making better glass

What's interesting is that, unlike most smartphones equipped with Gorilla Glass, Sonim's phones are produced with a different variation of the Corning formula—a formula that is about twice as thick, and stronger too.

"For us, at 2mm, if you drop it on a rock it doesn't break," says Plaschke. "All Gorilla Glass is very scratch resistant—ours just happens to be very, very difficult to break. You can hammer a nail and not break it."

However, there's a good reason why Gorilla Glass is so thin on a typical smartphone—it's because of touch. Capacitive touchscreens require the screen to be thin enough that the human body's electrical signals can be detected accurately by the digitizer underneath, something that becomes more difficult with Sonim's thicker glass. Worse still, Plaschke says his customers want a device that can be used just as easily with or without gloves, a feature most current smartphones struggle to provide. This will improve over time, of course (Corning's Gorilla Glass 2 is said to be even stronger than its predecessor, despite measuring a scant 0.8 mm). But for now it's one of a true rugged smartphone's biggest hurdles—next to battery life, that is.

Battling battery woes

Dismantle an iPad, and you'll see that the entire device is practically one giant battery. With a device footprint of that size, a long-lasting battery life is easy to hide. But when you enter smartphone territory, you have to work with the space you're given—which is actually quite small. This is partly due to manufacturing demands, where the standardized layout of internal components can't be always be adapted to accept non-standard battery sizes easily or cheaply.

Consumers, however, also play a part. Consumer demand for thinness means that a typical smartphone "has to weigh under 100g with a surface area of 100mm or less" to fit comfortably in a pant pocket, Plaschke says. "If you want to stay inside those constraints, you're limited to the size of the battery."

That's a problem, because Sonim phones typically offer two-to-three times more battery life than a typical feature phone—to the extent that his company's current line of phones offer up to 22 hours of talk time, or over one month of standby.

"That's a little bit longer than you're going to get with a typical smartphone," he laughs.

"So when I say we don't compete with the Samsung Rugbys or the Defys, it's because they're not thick, and they'll never get thick. Until we believe we can get 16 hours of battery life on an Android phone, it doesn't make sense to launch."