It was only a matter of time. The Internet offered so much more than Web searching. Even the ubiquitous landline telephone would eventually succumb to its appeal.

The Scottsdale, Ariz.-based market research firm In-Stat confirmed this in January when it announced that Internet protocol (IP) telephony had crossed over from an emerging technology to the mainstream choice for business voice. According to the company, user acceptance of IP telephony is high, with sales of IP lines in the first half of 2007 continuing to solidly outpace those of traditional lines as the move to IP telephony among businesses continues.

“The initial technical and operational challenges of IP telephony are behind it,” said Norm Bogen, In-Stat research director. He said the returns on investment and the productivity gains associated with the technology have proven the economics to be solid and “will continue to exceed those that could be realized with traditional telephony.”

According to In-Stat, 11.1 million IP lines were shipped worldwide in the first half of 2007, comprising  more than 80 percent of total shipments.