diff --git a/lapd/LAPDm_Types.ttcn b/lapd/LAPDm_Types.ttcn
index cb3f3f2..522aa4d 100644
--- a/lapd/LAPDm_Types.ttcn
+++ b/lapd/LAPDm_Types.ttcn
@@ -119,6 +119,18 @@
 		u := { u2 := '01'B, p_f := f, u := '011'B }
 	};
 
+	external function dec_LapdmAddressField(in octetstring stream) return LapdmAddressField
+		with { extension "prototype(convert) decode(RAW)" };
+
+	external function dec_LapdmCtrl(in octetstring stream) return LapdmCtrl
+		with { extension "prototype(convert) decode(RAW)" };
+
+	external function dec_LapdmCtrlU(in octetstring stream) return LapdmCtrlU
+		with { extension "prototype(convert) decode(RAW)" };
+
+	external function dec_LapdmLengthIndicator(in octetstring stream) return LapdmLengthIndicator
+		with { extension "prototype(convert) decode(RAW)" };
+
 	/* Format A is used on DCCHs for frames where there is no information field */
 	type record LapdmFrameA {
 		LapdmAddressField	addr,