diff --git a/docs/en/app/demo-board.md b/docs/en/app/demo-board.md
index e5fe7fbf..9811f07d 100644
--- a/docs/en/app/demo-board.md
+++ b/docs/en/app/demo-board.md
@@ -21,7 +21,7 @@
 - DC-Motor(with feedback encoder)
 - step motor with four-phase five-wire 
 - Radio frequency identification Reader
-- RS-458，RS232 series communication
+- RS-485，RS232 series communication
 
 <img src="assets/img/product_pics/app/Demo-Board/Demo-Board_03.jpg" width="250" height="250">
 
diff --git a/docs/zh_CN/app/demo-board.md b/docs/zh_CN/app/demo-board.md
index bf290441..99c021c2 100644
--- a/docs/zh_CN/app/demo-board.md
+++ b/docs/zh_CN/app/demo-board.md
@@ -30,7 +30,7 @@
 -  直流电机（带反馈）
 -  四相五线制步进电机
 -  无线射频识别读卡器
--  RS-458，RS232通信功能
+-  RS-485，RS232通信功能
  
 <img src="assets/img/product_pics/app/Demo-Board/Demo-Board_03.jpg" width="250" height="250">