diff --git a/library/GSM_RR_Types.ttcn b/library/GSM_RR_Types.ttcn
index 436273a..eed58df 100644
--- a/library/GSM_RR_Types.ttcn
+++ b/library/GSM_RR_Types.ttcn
@@ -268,7 +268,36 @@
 	} with { variant (len) "LENGTHTO(ma)" };
 
 	/* 10.5.2.25a */
-	type OCT3 PacketChannelDescription;
+	type record PktChDesc0Ind {
+		uint6_t		maio,
+		BIT1		ma_number_ind,
+		BIT1		change_mark1_valid,
+		BIT2		change_mark1
+	} with { variant "" };
+	type record PktChDesc0 {
+		BIT1		hopping,
+		BIT1		spare ('0'B),
+		uint10_t	arfcn optional,
+		PktChDesc0Ind	indirect optional
+	} with {
+		variant (arfcn) "PRESENCE(hopping = '0'B)"
+		variant (indirect) "PRESENCE(hopping = '1'B)"
+	};
+	type record PktChDesc1 {
+		uint6_t		maio,
+		uint6_t		hsn
+	} with { variant "" };
+	type record PacketChannelDescription {
+		uint5_t		channel_Type_spare,
+		uint3_t		tn,
+		uint3_t		tsc,
+		BIT1		presence,
+		PktChDesc0	zero optional,
+		PktChDesc1	one optional
+	} with {
+		variant (zero)	"PRESENCE(presence = '0'B)"
+		variant (one)	"PRESENCE(presence = '1'B)"
+	};
 
 	/* 10.5.2.25b */
 	type record DedicatedModeOrTbf {