In 2007, Telecom Transport Management announced $55 million in venture funding from Battery Ventures, Ignition Partners, Rally Capital and others. At the time of the deal, it also received a commitment for as much as $65 million more. Now, a portion of that round has come in, with the Seattle operator of back-haul networks for wireless carriers closing on an additional $20 million.

A spokesman for TTM confirmed the financing, but said an announcement was not planned since the company had already discussed the funding two years ago.

Founded in 2003 by former McCaw Cellular executives, TTM has created a fiber network system that can more efficiently direct phone calls and data from wireless towers to the carrier's switching stations. The startup is now led by Lynn Refer, who previously worked in executive roles at Ameritech and MFS Communications.

It competes against San Francisco-based FiberTower, a publicly-traded company with service revenue of $49.2 million last year.

TTM got some press earlier this month in a story in The Wall Street Journal about how the federal stimulus may help telecom companies. The story noted that TTM is applying for as much as $100 million in funds to build out its wireless network.

“The private markets are frozen these days, and absent the government funding, we would not be contemplating areas of our build-out,” TTM Chairman Mark Hamilton told the Journal.