Acme Packet Inc., which makes devices that help transmit voice and data over Internet networks, said second-quarter results are disappointing. “We are disappointed with our preliminary results,” CEO Andy Ory said. “Our top line results were principally impacted by continued weakness in the North American service provider market.” The Bedford company will release full results July 26. Also, a Wells Fargo equity analyst cut his rating to “market perform” from “outperform.”