diff --git a/library/GSM_RR_Types.ttcn b/library/GSM_RR_Types.ttcn
index b7e02ec..b4aff10 100644
--- a/library/GSM_RR_Types.ttcn
+++ b/library/GSM_RR_Types.ttcn
@@ -193,6 +193,11 @@
 		uint8_t		actual_ta
 	} with { variant "FIELDORDER(msb)" };
 
+	external function enc_SacchL1Header(in SacchL1Header hdr) return octetstring
+		with { extension "prototype(convert) encode(RAW)" };
+	external function dec_SacchL1Header(in octetstring stream) return SacchL1Header
+		with { extension "prototype(convert) decode(RAW)" };
+
 	template (value) SacchL1Header ts_SacchL1Header(uint5_t ms_power_lvl, boolean fpc, uint8_t actual_ta) := {
 		reserved := 0,
 		fpc := fpc,