diff --git a/mbus/mbus-protocol.c b/mbus/mbus-protocol.c
index c6916f9..368ca7f 100644
--- a/mbus/mbus-protocol.c
+++ b/mbus/mbus-protocol.c
@@ -265,9 +265,11 @@ mbus_frame_type(mbus_frame *frame)
 //
 // Possible checks:
 //
-// 1) Start/stop bytes
-// 2) length field and actual data size
-// 3) checksum
+// 1) frame type
+// 2) Start/stop bytes
+// 3) control field
+// 4) length field and actual data size
+// 5) checksum
 //
 //------------------------------------------------------------------------------
 int
@@ -289,6 +291,17 @@ mbus_frame_verify(mbus_frame *frame)
                         
                     return -1;
                 }
+                
+                if ((frame->control != MBUS_CONTROL_MASK_SND_NKE)                         &&
+                    (frame->control != MBUS_CONTROL_MASK_REQ_UD1)                         &&
+                    (frame->control != MBUS_CONTROL_MASK_REQ_UD1 | MBUS_CONTROL_MASK_FCB) &&
+                    (frame->control != MBUS_CONTROL_MASK_REQ_UD2)                         &&
+                    (frame->control != MBUS_CONTROL_MASK_REQ_UD2 | MBUS_CONTROL_MASK_FCB))
+                {
+                    snprintf(error_str, sizeof(error_str), "Unknown Control Code for Short Frame");
+                
+                    return -1;
+                }
 
                 break;
 
@@ -302,6 +315,18 @@ mbus_frame_verify(mbus_frame *frame)
                     return -1;
                 }
                 
+                if ((frame->control != MBUS_CONTROL_MASK_SND_UD)                         &&
+                    (frame->control != MBUS_CONTROL_MASK_SND_UD | MBUS_CONTROL_MASK_FCB) &&
+                    (frame->control != MBUS_CONTROL_MASK_RSP_UD)                         &&
+                    (frame->control != MBUS_CONTROL_MASK_RSP_UD | MBUS_CONTROL_MASK_DFC) &&
+                    (frame->control != MBUS_CONTROL_MASK_RSP_UD | MBUS_CONTROL_MASK_ACD) &&
+                    (frame->control != MBUS_CONTROL_MASK_RSP_UD | MBUS_CONTROL_MASK_DFC | MBUS_CONTROL_MASK_ACD))
+                {
+                    snprintf(error_str, sizeof(error_str), "Unknown Control Code for Long/Control Frame");
+                
+                    return -1;
+                }
+                
                 if (frame->length1 != frame->length2)
                 {
                     snprintf(error_str, sizeof(error_str), "Frame length 1 != 2");