Five blocks of frequencies in the 700-MHz band went on auction Thursday, with 214 approved bidders ranging from telecommunications companies like Verizon Wireless and AT&T to newcomers like Google and Chevron USA to small, local companies. Observers have speculated that the auction could bring in $10 billion to $30 billion, but the top bidders are not yet known because the bids are secret until the end of the auction.

The C and D Blocks

Two blocks in particular have attracted a lot of attention in recent months, the C and D blocks.

After months of lobbying for open-access rules by an alliance led by Google, the FCC had announced that the C block winner must allow the use of any compatible device or non-malicious software, assuming the minimum price was met.

Although other open-access requests were not adopted, including a requirement that the winner make the bandwidth available on a wholesale basis to third-party resellers, the initially reluctant AT&T and Verizon Wireless now have declared their support for open networks.

After the first day of bidding, the C block's high bid was $1.24 billion. The open-devices provision requires that a minimum price of $4.7 billion be met.

The D block would require that the winner allow public-safety agencies to use it in case of emergencies. The leading contender for that spectrum chunk had been Frontline Wireless, a startup which included former FCC chairman Reed Hundt, but that company recently announced it was ceasing operations because it was unable to complete its financing. The D block received a high bid of $472 million Thursday from its unknown suitor, but the minimum price is $1.3 billion.

Plenty of Time

There is plenty of time for the bids to match or exceed the minimums. The auction can take weeks to complete, and will only end when all bids have been submitted.

With the withdrawal of Frontline, it will interesting to see if the D block eventually meets the reserve price or goes higher, said Bill Ho, an analyst with industry research firm Current Analysis. "But it's really too early to tell" about possible trends or directions, he pointed out.

The auction, which observers have described as "the chance of a lifetime" and "a kind of a land grab," is potentially a major event in the evolution of American telecommunications. The networks resulting from the auction can be particularly valuable, because frequencies in the 700-MHz band can penetrate walls and various obstacles more effectively than other frequencies. They have been used for analog television since the beginning of the medium, but are being vacated as U.S. TV goes completely digital .

Winning their bids could change the business models of some companies. Google, in particular, is being watched because of its open-access insistence and its recent spearheading of an open-source Android mobile platform. If cable companies win their bids, they could remake their "triple-play" offerings of phone, cable and Internet access into a "quad-play" with wireless.