diff --git a/serial_task.cpp b/serial_task.cpp
index 494aec4..9401dc6 100644
--- a/serial_task.cpp
+++ b/serial_task.cpp
@@ -198,8 +198,9 @@ void serialRxTask(void *param) {
           if (linePos > 0) flushLineToQueues(lineBuf, linePos);
           continue;
         }
-        // Only accept printable ASCII (0x20~0x7E) and TAB (0x09)
-        if ((c >= 0x20 && c <= 0x7E) || c == '\t') {
+        // Accept printable ASCII + UTF-8 multibyte (한글 등)
+        // Skip only control chars (0x00~0x1F) except TAB
+        if (c >= 0x20 || c == '\t') {
           lineBuf[linePos++] = c;
         }
       }