Silicon Valley based RingCentral offers businesses a virtual telephone system (they say “Sound more professional, look like a bigger company”). It’s sort of a super-Vonage, but targeted to businesses first. And they have a lot more features, including a virtual PBX to manage multiple lines and “greetings recorded by professional voice talent.”

The company took $12 million in late 2007 from Sequoia Capital and Khosla Ventures. Today they announced a second round, also $12 million. The round was led by DAG Ventures, which often follows Sequoia and other well known venture capitalists in second, more expensive rounds.

RingCentral provides phone system integration and utilities to a traditionally under-served category, small to medium sized businesses. Similar to GrandCentral, RingCentral (founded in 1998) uses a virtual number to offer more services to their users existing mobile, fax, and landlines. RingCentral numbers can feature an auto-attendant, multiple extensions, call forwarding, voicemail, click-to-call, screening, logs, and Outlook integration.

On Monday, the company will announce they raised a $12 million series A financing from two highly respected firms, Khosla Ventures and Sequoia. RingCentral is also adding a new CFO, Dinesh Lathi, who was an ex-VP of eBay. They have currently provisioned over 100,000 numbers and serve over 40,000 paying customers with plans ranging from $9.99 per month to $24.99 per month.

With the recent acquisition of GrandCentral, VOIP as a utility instead of as a means for cheap calling rates has been a more successful strategy for the new telcos as of late. Virtual numbers, while requiring people to switch numbers, allow customers to use their phones without needing to download or adjust their calling behavior with new programs.

RingCentral is based in Redwood City and currently has 80 employees.