Have you seen the new(ish) credit cards with embedded square chips on the front? Or heard travel friends throw around the phrases "chip-and-PIN" or "chip-and-signature"? While these cards -- otherwise known as smart cards or EMV cards -- are a relatively recent product from American banks, they're widely used in many regions abroad, particularly in Europe as well as in Australia and parts of Asia. In fact, EMV cards are so common that cards with magnetic stripes, like most from home, can't be used in some situations abroad.

Before we launch into a few examples, it's worth noting that there's a difference between chip-and-PIN cards and chip-and-signature cards -- namely that, as the names suggest, the former requires the owner to enter a PIN with each transaction while the latter requires a signature on the receipt. It's an important difference, too, especially since there are very few PIN-enabled credit cards available from American banks, though we're starting to see more chip-and-signature cards.

The bad news is that some machines and vendors require your personal four-digit code to process a transaction, which means a chip-and-sign card won't work, either. The good news is that this isn't true across the board -- the all depends on the region and the individual businesses -- and more banks are getting ready to distribute chip-and-PIN cards. Barclaycard, Wells Fargo, USAA, and PenFed are some that already offer PIN-enabled cards, while Chase and Target plan to roll them out in the next year.

So what could you need an EMV card for?

1. Ticket kiosks: Increasingly, self-serve kiosks in Europe that spit out train tickets, event passes, and anything else will only accept chip-and-PIN cards. Paris and Amsterdam are just two cities out of many that require you to enter a valid PIN. If you’re without a PIN-enabled card or cash, you’ll likely have to stand in a queue to speak to a human being.

2. Onboard purchases: Many international airlines and an increasing amount of domestic airlines no longer take cash for inflight purchases. If you're flying a European carrier, particularly a regional one like Ryanair, there's a big chance you'll only be able to use an EMV card. Hankering for a gin-and-tonic at 30,000 feet -- or even a small bottle of water? You better have the proper plastic.

3. Dining and shopping: Especially when you get out to less touristy areas, many establishments and vendors won't have machines that can swipe a magnetic strip. That said, if you have a chip-and-signature card that gets rejected, ask if the machine has a "no-PIN" button that will print a receipt. After all, in areas where almost everyone has EMV cards, vendors might not even know that this function exists. If it's not an option or if the vendor simply doesn't want to forgo that layer of security, though, you're out of luck.

4. Gasoline: Eurotripping is great… until your rental runs out of fuel. All across Europe, many petrol stations are converting their pay-at-the-pump stables to EMV payment methods. Success with chip-and-signature cards varies generally. If they don't work, you'll just have to arrive during business hours and pay at the counter.

5. Toll booths: Here's one area that people with chip-and-signature cards seems to have the most failure with. As with the automated machines, you have to punch in a PIN. You should do your research before any trip, but we've heard many complaints about the booths in France and Belgium in particular.