PETALUMA -- Calix, Inc. (NYSE: CALX) reported a 19.4 percent decrease in revenue for the quarter ended June 30, compared to the same quarter in 2011.

The Petaluma-based developer of broadband data systems and software reported revenue of $78.9 million, down from $98 million in the second quarter of last year.

The reporting followed an announcement earlier this month that the company expected lower-than-estimated revenue in the second quarter, with new estimates showing revenue flat with the first quarter of the year at $79 million. Original estimates were between $93 million and $97 million.

"As we noted on July 11th when we announced preliminary Q2 results, softness in demand across multiple customer markets led to an unexpected slowdown in capital expenditures by service providers increasingly concerned about macro-economic conditions and uncertainties associated with the implementation of regulatory reforms," said Carl Russo, president and CEO of Calix, in today’s release. "In spite of these challenges, Calix maintained gross margins at expected levels while reducing inventories and producing another quarter of positive cash flow."

Non-GAAP net income for the second quarter was $1.9 million, or four cents per diluted share. During the same quarter last year, the company had a net income of $7.9 million, or 16 cents per diluted share.

The GAAP net loss for the quarter was $7.1 million or 15 cents per diluted share, which include measures like stock-based compensation and the amortization of acquisition-related intangible assets from the merger with Occam Networks. In 2011, the second quarter GAAP net loss was $17.6 million.

Calix’s stock tumbled 5.92 percent today, to $4.61.