diff --git a/library/GSM_RR_Types.ttcn b/library/GSM_RR_Types.ttcn
index 980020e..335e290 100644
--- a/library/GSM_RR_Types.ttcn
+++ b/library/GSM_RR_Types.ttcn
@@ -198,7 +198,10 @@
 	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) := {
+	template (value) SacchL1Header
+	ts_SacchL1Header(uint5_t ms_power_lvl,
+			 uint8_t actual_ta,
+			 boolean fpc := false) := {
 		reserved := 0,
 		fpc := fpc,
 		ms_power_lvl := ms_power_lvl,