To　establish　data　connection　in　industrial　wireless　networks,　the　engineer　has　to　enter　the　address　of　the　target　machine　or　manually　select　it　from　a　list.　Since　the　machines　are　densely　deployed　in　the　plant,　the　manual　data　connection　becomes　a　non-trivial　issue　which　may　lead　to　connection　error　and　waste　of　time.　The　existing　technologies,　such　as　QR　code　scanning　and　proximity　estimation,　simplify　the　process　of　data　connection　to　the　closest　node.　However,　they　can　not　be　used　to　connect　with　any　node　located　in　line-of-sight　of　the　engineer,　and　thus　limits　their　application.　In　this　paper,　we　propose　a　scheme　called　LightCon　which　controls　the　display　module　(LCD　screen　or　LED　light)　of　nodes　to　display　different　visible　symbols　such　as　colors　and　numbers,　thus　the　engineer　can　select　the　corresponding　symbol　on　the　mobile　device　to　establish　connection.　Moreover,　symbol　assignment　algorithms　are　proposed　to　reduce　the　complexity　of　symbol　selection　when　the　number　of　nodes　are　greater　than　the　number　of　symbols.　The　theoretical　and　experimental　results　prove　that　LightCon　reduces　the　complexity　of　line-of-sight　connection　with　guaranteed　accuracy.