Secure communications products and services provider Vislink said trading in the first quarter of 2010 remained mixed with underlying order intake down 15% on the corresponding period of 2009.The order backlog at the end of March 2010 was £17.6m, down from £20.3m at the end of 2009.On the positive side, sales pipelines, which represent the total value of identified opportunities, have grown by around 15% since January, though the company warned that "visibility as to when opportunities will be converted into orders remains opaque." "As a result of the slow order in-take in the first quarter, the board anticipates that the outturn for the first half of the year will be below that of the first half of last year, and the results for the year will be heavily weighted towards the second half," chief executive Duncan Lewis said.