Shares of phone and data network equipment maker Acme Packet fell after it reported a second-quarter loss due to a slowdown in spending by North American service providers. Acme also lowered its outlook for the year. Second-quarter results were in line with Acme’s lowered forecast, but guidance disappointed investors. There have been delays in implementing a new system for phone calls by AT&T and Verizon, one analyst said. For the year, Acme expects net income to be 43 cents to 47 cents.