diff --git a/src/core/operations/ManchesterDecode.mjs b/src/core/operations/ManchesterDecode.mjs
index bfde046a..d71bfd53 100644
--- a/src/core/operations/ManchesterDecode.mjs
+++ b/src/core/operations/ManchesterDecode.mjs
@@ -25,6 +25,13 @@ class ManchesterDecode extends Operation {
         this.inputType = "string";
         this.outputType = "string";
         this.args = [];
+        this.checks = [
+            {
+                pattern: "(01|10)*",
+                flags: "",
+                args: []
+            }
+        ];
     }
 
     /**