Putting an end to rampant industrywide speculation, carrier Sprint PCS ( PCS) is planning to unveil its high-speed data network Thursday, in a development that it hopes will drive more wireless customers back into the fold, according to industry sources.

The launch will give Sprint the first nationwide high-speed wireless data service, which promises to give cell-phone users access to email and Web downloads at speeds faster than a dial-up modem.

It's an important milestone for the company, as Wall Street has privately derided it for not being able to officially commit to a launch date. For more than a year, Sprint PCS has told investors that it is preparing for a "summer" launch, falling short of a specific date.

The subject of its official launch date has been shrouded in secrecy for some time, according to sources familiar with the network, as problems with some key components to the system have yet to be worked out. It remains unclear whether such issues, involving the ability to bill for services, will be operating by Thursday. A Sprint spokeswoman declined to comment on the date.

In early July, an executive at Audiovox ( VOXX), which plans to sell a device that operates on Sprint's new network, told investors that the company planned to begin selling its new Thera device on Aug. 10.

That date has become the unofficial date Wall Street expects Sprint to launch the network. The Thera is a handheld computer and phone hybrid that runs on Microsoft's ( MSFT) PocketPC operating system and is manufactured by Toshiba.

The launch of the data network, which is not expected to materially contribute to the bottom line in any significant manner until 2003 at the earliest, is important to the company. This is because it is hoped that promotion surrounding the news will drive more new customers back into Sprint stores, said executives on a conference call in July.

Given the date, it's no surprise that Verizon Wireless, a joint venture between Vodafone ( VOD) and Verizon ( VZ), just days ago began to publicize discounts for new subscribers to its high-speed network.

In recent trading, Sprint PCS shares gained 7 cents, or 2.19%, to $3.27.