Acme Packet Inc forecast a fourth quarter that lagged analysts' estimates and cut its 2011 outlook on concerns of crippled capital spending budgets at its telecommunication customers in North America.

Shares of the network infrastructure provider, which have lost almost two-thirds of their value since touching a year-high of $84.50 on April 29, fell to $25.12 in trading after the bell. They closed at $31.81 on Tuesday on Nasdaq.

Bedford, Massachusetts-based Acme's customers such as AT&T and Verizon have been cautious with their spending, leading to reduced orders, as AT&T grappled with a now-terminated deal with T-Mobile and Verizon tackled labor issues.

The company, which competes with Cisco Systems, Huawei Technologies and Sonus Networks, expects fourth-quarter adjusted earnings of 26 cents to 28 cents per share on revenue of $84 million to $86 million.

Analysts are expecting Acme to earn 37 cents a share on revenue of $93.4 million, according to Thomson Reuters I/B/E/S.

The company also cut its full-year earnings outlook to 66 cents to 68 cents per share on revenue of $308 million to $310 million. It had earlier forecast 2011 earnings of 78 cents to 82 cents per share on revenue of $315 million to $320 million.

(Reporting by Siddharth Cavale in Bangalore; Editing by Joyjeet Das)

Broadband Broadband Fall