diff --git a/public-trunk/GSM/GSML1FEC.cpp b/public-trunk/GSM/GSML1FEC.cpp
index a8ac97b..4e56c0e 100644
--- a/public-trunk/GSM/GSML1FEC.cpp
+++ b/public-trunk/GSM/GSML1FEC.cpp
@@ -308,6 +308,19 @@ void L1Encoder::sendIdleFill()
 
 
 
+unsigned L1Decoder::ARFCN() const
+{
+	assert(mParent);
+	return mParent->ARFCN();
+}
+
+
+TypeAndOffset L1Decoder::typeAndOffset() const
+{
+	return mMapping.typeAndOffset();
+}
+
+
 void L1Decoder::open()
 {
 	mLock.lock();
diff --git a/public-trunk/GSM/GSML1FEC.h b/public-trunk/GSM/GSML1FEC.h
index 4db807d..bf402da 100644
--- a/public-trunk/GSM/GSML1FEC.h
+++ b/public-trunk/GSM/GSML1FEC.h
@@ -295,8 +295,12 @@ class L1Decoder {
 	/** Accept an RxBurst and process it into the deinterleaver. */
 	virtual void writeLowSide(const RxBurst&) = 0;
 
-	/** Return the decoder timeslot number. */
+	/**@name Components of the channel description. */
+	//@{
 	unsigned TN() const { return mTN; }
+	unsigned ARFCN() const;					///< this comes from mUpstream
+	TypeAndOffset typeAndOffset() const;	///< this comes from mMapping
+	//@}
 
 
 	protected: