Here come the pay phones

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Millions of phones running Google Inc.’s Android operating system offer a similar service called Google Wallet that relies on the same technology as Apple Pay. So does a service called Softcard that’s offered by three of the biggest cellphone companies — AT&T, T-Mobile, and Verizon Wireless. Meanwhile, a startup in Burlington called LoopPay hopes to outflank its giant rivals with a phone payment option that works in millions more retail stores than the Apple and Google systems.

All these services allow you to stash your credit card data inside an encrypted file on your phone.

You can manually type in the card number or use the phone’s camera to scan it in.

Then you can wirelessly transmit the data at checkout instead of swiping a plastic card through a slot.

Apple Pay, Google Wallet, and Softcard all use a technology called near-field communication. A chip embedded in the phone sends an encrypted signal to a compatible checkout terminal.

Trouble is, hardly any terminals are compatible. These three payment methods work at only 5 percent of the nation’s 3.8 million retail stores.

But when they work, it’s pretty cool.

As you’d expect, Apple Pay is the coolest, thanks to the i-Phone 6 fingerprint reader. I used it to buy lunch the other day at the Star Market on Morrissey Boulevard. At checkout, I just tapped the phone against the credit card terminal. Apple’s financial app Passbook lit up and asked for my thumbprint. I touched the button, and two seconds later the deal was done.

I later bought a cup of Starbucks coffee with the Google Wallet app on my Android phone. Same procedure — almost. But this time, I had to enter a four-digit PIN number, making the process a little less slick. Still, it worked.

I’ve had similar success with Softcard, but setting it up was a nuisance. Softcard requires a special secure SIM card, forcing a trip to an AT&T store. In addition, Softcard is compatible only with American Express, Chase, and Wells Fargo credit cards.

Google Wallet works with any Visa, MasterCard, Discover, or American Express card. Apple Pay doesn’t work with Discover, but is compatible with cards from most major banks, including Capital One, Bank of America, Citi, Chase, and Wells Fargo.

Still, none of these services works at most stores. Credit card companies are adopting more advanced and secure card readers, but the process will take another three to five years.

That’s good news for Will Graylin, LoopPay’s chief executive. His company makes a $90 case that snaps around an iPhone 5 or 5S. Inside is a radio that transmits the user’s credit card number to the magnetic strip reader found in old-school card swipe machines. Graylin says LoopPay will work with about 90 percent of existing credit card terminals. It comes with an electronic fob that you can give to restaurant waiters who normally take your credit card out back. They can use this fob to enter your card data, though you’ll have to teach the waiter how it works.

And even with a bit of instruction, LoopPay doesn’t always come through. Some terminals welcomed it; others flashed the message “Card Read Error.” You have to hold the phone close to the card reader at just the right spot, but it wasn’t always easy to figure out where that was. Besides, LoopPay isn’t as secure as the other phone payment systems, which transmit a unique code for each transaction. LoopPay won’t offer this feature until next year.

That’s a critical drawback, because the enhanced security of phone-based payment is the best reason to use it. LoopPay is costly, inconsistent, and for now, not terribly secure. Apple Pay, Google Wallet, and Softcard offer tougher security than today’s credit cards, and they’re easy to use but only where they work, which, for now, is hardly anyplace.

So the next time I hold up the checkout line, I’ll probably be fumbling with my wallet, not my phone.

Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him on Twitter @GlobeTechLab.