German engineering giant Siemens is working with Amazon.com to test new cloud-based voice and communications software. Siemens rolled out the experimental product at the VoiceCon conference in Orlando and is gauging customer interest. The software runs on Amazon's Elastic Compute Cloud (EC2) -- and marks another interesting collaboration for Amazon in the cloud computing arena.

Siemens' cloud applications include Voice over Internet Protocol (VoIP) and so-called "unified communications" (for example, integrating voice and email or converting voice mail to text). Siemens is hoping it will appeal to cash-strapped businesses that want the software but don't want to go to the trouble or expense of paying for their own infrastructure.

"The technology can be complex for a small or medium-sized business," said Paul McMillan, Siemens director of unified communication techical vision and strategy. "We've elimated a lot of steps for the customer."

McMillan said Siemens is considering a pay-as-you-go cost structure for its cloud services (similar to Amazon's) or a subscription model. He said the company is also exploring the idea of opening its cloud services up to third-party developers.

The linkup with Siemens is Amazon's latest enterprise partnership in the cloud. The Seattle online retailer has teamed with a number of other companies, most recently IBM.

There are other firms working with telephony software in the cloud. Twilio, a startup founded by Amazon Web Services alum Jeff Lawson, allows developers to build and scale phone system applications in the cloud. The company scored an undisclosed amount of funding from the Founders Fund and Mitch Kapor in early March.