 Plantronics Inc. shares soared 25 in after-hours trade Thursday, after the audio and video conferencing products provider blew past adjusted earnings estimates for its fiscal second quarter and offered upbeat guidance for the current quarter. The company, which operates under the brand name Poly, posted a net loss of 13.405 million, or 33 cents a share, narrower than the loss of 29.910 million, or 65 cents a share, posted in the year-earlier period. 