diff --git a/include/patty/ax25/macros.h b/include/patty/ax25/macros.h
index cb5a42a..426afc7 100644
--- a/include/patty/ax25/macros.h
+++ b/include/patty/ax25/macros.h
@@ -47,7 +47,7 @@
     ((c & 0xe0) >> 5)
 
 #define PATTY_AX25_CONTROL_UNNUMBERED_SABM(c) \
-    (((c & 0xe0) == 0x10) && ((c & 0x0f) == 0x0f))
+    (((c & 0xe0) == 0x20) && ((c & 0x0f) == 0x0f))
 
 #define PATTY_AX25_CONTROL_UNNUMBERED_DISC(c) \
     (((c & 0xe0) == 0x20) && ((c & 0x0f) == 0x03))