(CNN) -- The Verizon iPhone train started rolling this week, but Apple's main smartphone competitors aren't about to be left at the station.
This week, cellular carriers released details about a trio of upcoming smartphones, all of which run an older version of Google's Android operating system.
AT&T announced a March 6 release deadline for the Atrix 4G, a Motorola Mobility "transformer" phone that grabbed the spotlight at the Consumer Electronics Show last month.
With a speedy dual-core processor inside, the Arix can be used as a media center or limited-function PC when connected to a television or monitor using a dock accessory. Motorola will also sell a laptop shell that allows the Atrix to essentially convert into a sort of netbook, complete with a keyboard.
New details about the much-anticipated Atrix came on the same day Verizon Wireless began letting current customers pre-order the iPhone 4, formerly exclusive to AT&T in the U.S.
At $200 with a two-year contract, the Atrix will be among the first to run on AT&T's faster data network and carry the "4G" branding. (For $500 with a contract, you get the phone and the laptop dock; the latter is also sold separately for $500.)
The Atrix, an AT&T exclusive, will be available for pre-order starting on February 13.
On the same day, AT&T will begin selling another so-called 4G phone.
The second-largest U.S. carrier by subscribers announced the launch date and a $100 price tag, two-year agreement required, for HTC's Inspire 4G. That info came on Tuesday, kicking off a big week for smartphone news. The Inspire has a 4.3-inch screen -- the same large size as the Evo 4G.
The new device will be the inaugural smartphone to offer AT&T's Mobile Hotspot service.
Having long struggled to support the bandwidth needs of its millions of smartphone subscribers, AT&T lags behind competitors in offering this feature. Customers will have to pay an extra $20 per month to use the feature, which adds 2 gigabytes of wireless internet usage, the carrier said on Wednesday.
T-Mobile USA, the fourth-largest U.S. network, said on Tuesday that it expects to begin selling the Galaxy S 4G from Samsung Electronics this month. It's similar to Samsung's several other Android handsets, but this one is compatible with T-Mobile's faster data network.
All three of these new smartphones, strangely, come with a seven-month-old version of Android, called Froyo.
Since releasing that version, Google launched another called Gingerbread, which powers a Samsung-made phone called the Nexus S. Google held a news conference on Wednesday to say developers are close to releasing the first device that will run the next Android, called Honeycomb, this month.