Phone.com agreed to acquire start-up Onebox.com for $850 million in stock, potentially marking the beginning of a shakeout among a variety of new communications companies.

The move highlights the changing nature of the communications industry, in which traditional voice services, prevalent wireless technology and the Net are melded into an easy-to-use package. Upstart wireless Internet software maker Phone.com is working with mobile phone manufacturers such as Nokia and Motorola to deploy its "microbrowser" for wireless Net access. With today_s purchase of Onebox, Phone.com will be able to add a variety of services such as Net-based email, voicemail and faxes. It also will gain access to 2.5 million registered Onebox users. "What_s becoming possible now is the combination of voice and data into a variety of powerful new services for consumers," said Ben Linder, Phone.com_s vice president of marketing. Phone.com executives believe partnerships and mergers are the first steps in combining the limited abilities of traditional communications services with dozens of new--but sometimes not-so-convenient--Internet-based services. But given some hesitancy concerning new ways of combining Net-based communications with traditional methods, stock in Phone.com, formerly Unwired Planet, has slipped some since announcing the acquisitions. Phone.com shares have risen rapidly and split once since its initial public offering last summer and have traded as high as $175 and as low as $16.13. International Data Corp. estimates the U.S. integrated messaging market will grow to 25 million mailboxes from 750,000 today, making the market worth $5 billion.