Withdrawal symptoms? Here's how to make your iPhone a BlackBerry

Las Vegas: If you love your iPhone but would prefer a physical keyboard, Typo could be for you.

But you might want to order soon. BlackBerry, the company that made physical typing on mobile devices an addictive craze, is suing Typo Products LLC, accusing it of copying its world-famous keyboard.

The idea's great: With BlackBerry's ongoing struggles and the rise of touch-only iPhones and Android phones, physical keyboards on mobile devices were headed to obsolescence. That's a big loss for people who can use their thumbs to type as fast as 60 words per minute on a physical keyboard.

Enter the Typo Keyboard, a Ryan Seacrest-backed phone case that was showcased at this week's International CES gadget show in Las Vegas.

How it works: Typo's keyboard slips over an iPhone 5 or iPhone 5S like a protective case.

Its similarities with BlackBerry phones are notable: It has angle-cut keys suitable for thumb-typing. The keyboard layout is nearly identical - for example, with parentheses above the "T'' and "Y'' instead of the "9'' and "0'' on a typical keyboard. Thick silver bars separate rows of keys.

Physically, there are a few differences. Because the Typo case covers the iPhone's home button, it added one with the same function on the bottom right. There's a Bluetooth function on the "0'' key so the Typo can connect to the iPhone wirelessly. A light bulb key on the bottom left gives Typo's keys some lighting to use in dark environments.

The dispute: In a federal lawsuit filed Friday in San Francisco, BlackBerry Ltd. alleges that "Typo chose to copy BlackBerry's iconic keyboard design" and is making money off of BlackBerry's widespread recognition and goodwill.

Typo responded in a statement that BlackBerry's claims "lack merit" and that the company is excited about its "innovative keyboard design."

Look and feel: In my hands, the Typo works fine - just like a BlackBerry - except it is blocked from using Apple Inc.'s autocorrect function while typing. So that means you have to tap misspelled words that are underlined in red later and choose from options to fix them. If you have an iPhone 5S, the fingerprint sensor will be covered up, so you'll have to resort to inputting a passcode.

Development: Laurence Hallier, the CEO and co-founder of Typo, said testers of the device included BlackBerry users and others.

"We wanted that thumb-typing like the BlackBerry," he said. "We went out and priced it out. We built prototypes. It took us 18 months."

Typo Products is a Los Angeles startup co-founded by Seacrest and Hallier.

Availability: Typo sells for $99 and is expected to start shipping on Monday. It works only with the iPhone 5 and 5S, not the 5C or older iPhones.