Although　power　line　communication　(PLC)　is　not　a　new　technology,　its　use　to　support　communication　with　low　rate,　low-voltage　requirements　are　still　the　focus　of　ongoing　research.　In　access　domain　PLC　(abbreviated　as　AD-PLC),　its　applications　including　state　control,　home　automation　systems,　lighting　control,　air-conditioning　control,　low　speed　communication　networks,　automatic　meter　reading,　advertising　signs,　fire　and　security　systems,　etc.　It　opened　up　a　highly　flexible,　effective　and　simple　data　transmission　channel　for　many　industrial　applications　and　controlling　requirements.　Basis　on　the　power　line　channel　model　theory,　the　author　conducted　a　field　test　about　the　packets　error　rate,　transmission　delay　and　communication　margin　areas.　The　analysis　of　the　measured　data　show　that　we　can　achieve　low　rates,　long　distance　and　reliable　transmission,　and　having　greater　communication　channel　margin　by　the　way　of　Ack4try　(data　confirmed)　and　imposing　the　appropriate　level　of　transmission.　In　addition,　the　tests　also　verify　the　fact　that　the　bahaviour　of　power　line　channel　is　different　when　the　same　signal　transmission　in　different　directions.　©　2009　IEEE.