Now playing: Watch this: Surface on the sideline: how tablets work at an NFL game

It's starting to get pretty cold for a lot of NFL teams. Rainy, too. I entered MetLife stadium and stepped onto the damp FieldTurf on a Monday night that dipped into the low 40s, in the middle of unexpected showers. Perfect weather to check out weatherproofed tablets.

Microsoft's Surface tablets have been deployed on NFL sidelines since the start of this season, part of a partnership of which you're probably well aware. (CBS, CNET's parent company, broadcasts AFC and Thursday Night NFL games, but this Monday night game was broadcast by ESPN.) From a distance, it looks like the coaches on TV are holding iPads in thick rubber cases.

You might wonder what they're doing on those tablets. Well, it's actually not that complicated.

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There isn't much tech allowed on NFL sidelines. You can't use a cell phone, and thanks to another partnership with Bose, you can't even wear certain headphones. Coaches used to -- and still do -- use printers for pictures of plays, taken by cameras in the end zones and high up at midfield. These pictures get laminated and placed in binders, so coaches, staff and players can analyze what formations teams have used throughout the game.

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The Surface tablets replicate this, but faster and with a bit more interactivity. The sideline and end zone photos now get sent directly to the Surface tablets, in color, and do it faster than printers can print, plus they do it all during plays, versus after. Within the Surface's customized app, coaches can annotate, too, marking pictures up and saving the notes to their own profile.

A lot of broadcasters, and even NFL players, are having problems telling the difference between Surface tablets and iPads. But there is a difference: these Surfaces are customized, engineered and weatherproofed. They have a stylus that can write in the rain. And they're single-purpose: at the moment, they're one-app tablets.

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Each sideline gets 13 Surface tablets, linked to one of two separate secure wireless networks: one for each team. These are Microsoft Surface Pro 2 tablets, not the newer Surface Pro 3 , and made specifically to withstand rain and elements, plus they're given an additional ruggedized case. I tried using the non-capacitive stylus in some pretty heavy rain and it wrote on the screen just fine. They're meant to work in extreme cold too (120 to -10 degrees Farenheit; 48 to -23 degrees Celsius), although there's also a dedicated climate-controlled charging and data-syncing cabinet to store them when they're not in use. And they're made to have better visibility in direct sunlight. I tried them at night so it was hard to tell the difference, but plenty of NFL teams have been using them during bright afternoon games and it seems like all has gone well.

The software that runs on these tablets is limited to that photo-delivery function: you can't switch networks or use them for any other purpose. They're basically simplified, purpose-built tools. That's also by design, for now, as the NFL restricts teams to just using those photographs. The type of multi-view camera systems and real-time running stats we're used to on broadcasts just don't happen down here. For communications, of course, you can still call the booth or speak over headset (currently via a partnership with Bose).

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Microsoft invited myself and several of our CNET crew to check out these tablets first-hand. I'm a lifetime New York Jets season-ticket holder, but I'd never been on the actual field before, and I had never seen how these customized tablets actually worked. Our brief tour was guided by Tim Tubito, the director of video for the New York Jets and who oversees the filming and editing of all Jets games, and James Bernstrom, product marketing director for Microsoft. After that, we had to leave the field so the Jets and Miami Dolphins could get on with their game prep.

Watching from behind the Dolphins bench on the sidelines (which we weren't able to photograph, due to NFL restrictions), I noticed something -- several coaches and players weren't using the Surface tablets at all. They were using print-outs in binders.

That's something to keep an eye on as the NFL season heads toward the playoffs in the cold, rain and snow: in bad weather, old habits die hard.