If you’re a chief technology officer interested in voice over Internet Protocol (VoIP) and like numbers to support your decision-making, you might find these interesting.

Equant NV, a leading provider of international telecom services to large businesses, reported last week an 85 percent increase in the number of customer sites using VoIP — up to 1,300 from 700 — over the past 12 months. More than 130 multinational corporations now subscribe to the service, or about 10 percent of Equant’s total customer base, with demand steadily increasing, the company said.

“In the corporate sector, it’s now relatively easy for companies to migrate to VoIP and the savings are significant,” said Ian Cox, an analyst with Juniper Research Ltd. and author of the report Voice over IP and Network Convergence.

For instance, VoIP calls between company locations, “on-net” calls, are free of charge, according to Cox. “This is a big incentive — one of several — for corporations to move away from public-switched telephone networks,” he said.

Cox also expects calls from IP-virtual private networks (VPNs) to grow rapidly as corporations take advantage of network convergence to reduce their communication costs.

In April 2002, Equant launched one of the first end-to-end IP-based voice services based on IP-private branch automatic exchange (PBA) technology from Cisco Systems Inc., the service provider said. In the third quarter, it plans to add IP telephony systems from Avaya Inc. and Nortel Networks Corp.

Following recent regulatory approval in 17 countries, Equant, a wholly owned subsidiary of France T