diff --git a/Control/CallControl.cpp b/Control/CallControl.cpp
index 891562b..9a653f9 100644
--- a/Control/CallControl.cpp
+++ b/Control/CallControl.cpp
@@ -137,9 +137,9 @@ void forceSIPClearing(TransactionEntry *transaction)
 	}
 	else { //we received, respond and then don't send ok
 		//changed state immediately to canceling
-		transaction->MODSendUNAVAIL();
+		transaction->MODSendERROR(NULL, 480, "Temporarily Unavailable", true);
 		//then canceled
-		transaction->MODWaitForUNAVAILACK();
+		transaction->MODWaitForERRORACK(true);
 	}
 }
 
@@ -337,8 +337,8 @@ bool callManagementDispatchGSM(TransactionEntry *transaction, GSM::LogicalChanne
 				transaction->MODWaitFor487();
 			}
 			else { //if we received it, send a 4** instead
-				transaction->MODSendUNAVAIL();
-				transaction->MODWaitForUNAVAILACK();
+				transaction->MODSendERROR(NULL, 480, "Temporarily Unavailable", true);
+				transaction->MODWaitForERRORACK(true);
 			}
 			transaction->GSMState(GSM::NullState);
 			return true;
@@ -866,7 +866,7 @@ void Control::MOCController(TransactionEntry *transaction, GSM::TCHFACCHLogicalC
 				TCH->send(GSM::L3Progress(L3TI));
 				break;
 			case SIP::Timeout:
-				LOG(NOTICE) << "SIP:Timeout, reinvite";
+				LOG(ALERT) << "MOC INVITE Timed out. Is SIP.Proxy.Speech (" << gConfig.getStr("SIP.Proxy.Speech") << ") configured correctly?";
 				state = transaction->MOCResendINVITE();
 				break;
 			default:
diff --git a/Control/TransactionTable.cpp b/Control/TransactionTable.cpp
index 4cff71a..3dbf66b 100644
--- a/Control/TransactionTable.cpp
+++ b/Control/TransactionTable.cpp
@@ -420,10 +420,10 @@ SIP::SIPState TransactionEntry::MODSendBYE()
 	return state;
 }
 
-SIP::SIPState TransactionEntry::MODSendUNAVAIL()
+SIP::SIPState TransactionEntry::MODSendERROR(osip_message_t * cause, int code, const char * reason, bool cancel)
 {
 	ScopedLock lock(mLock);
-	SIP::SIPState state = mSIP.MODSendUNAVAIL();
+	SIP::SIPState state = mSIP.MODSendERROR(cause, code, reason, cancel);
 	echoSIPState(state);
 	return state;
 }
@@ -452,10 +452,10 @@ SIP::SIPState TransactionEntry::MODResendCANCEL()
 	return state;
 }
 
-SIP::SIPState TransactionEntry::MODResendUNAVAIL()
+SIP::SIPState TransactionEntry::MODResendERROR(bool cancel)
 {
 	ScopedLock lock(mLock);
-	SIP::SIPState state = mSIP.MODResendUNAVAIL();
+	SIP::SIPState state = mSIP.MODResendERROR(cancel);
 	echoSIPState(state);
 	return state;
 }
@@ -476,10 +476,10 @@ SIP::SIPState TransactionEntry::MODWaitForCANCELOK()
 	return state;
 }
 
-SIP::SIPState TransactionEntry::MODWaitForUNAVAILACK()
+SIP::SIPState TransactionEntry::MODWaitForERRORACK(bool cancel)
 {
 	ScopedLock lock(mLock);
-	SIP::SIPState state = mSIP.MODWaitForUNAVAILACK();
+	SIP::SIPState state = mSIP.MODWaitForERRORACK(cancel);
 	echoSIPState(state);
 	return state;
 }
diff --git a/Control/TransactionTable.h b/Control/TransactionTable.h
index 7cfceed..5a4568f 100644
--- a/Control/TransactionTable.h
+++ b/Control/TransactionTable.h
@@ -202,14 +202,14 @@ class TransactionEntry {
 	void MTCInitRTP() { ScopedLock lock(mLock); mSIP.MTCInitRTP(); }
 
 	SIP::SIPState MODSendBYE();
-	SIP::SIPState MODSendUNAVAIL();
+	SIP::SIPState MODSendERROR(osip_message_t * cause, int code, const char * reason, bool cancel);
 	SIP::SIPState MODSendCANCEL();
 	SIP::SIPState MODResendBYE();
 	SIP::SIPState MODResendCANCEL();
-	SIP::SIPState MODResendUNAVAIL();
+	SIP::SIPState MODResendERROR(bool cancel);
 	SIP::SIPState MODWaitForBYEOK();
 	SIP::SIPState MODWaitForCANCELOK();
-	SIP::SIPState MODWaitForUNAVAILACK();
+	SIP::SIPState MODWaitForERRORACK(bool cancel);
 	SIP::SIPState MODWaitFor487();
 
 	SIP::SIPState MTDCheckBYE();
@@ -241,6 +241,9 @@ class TransactionEntry {
 	void saveBYE(const osip_message_t* bye, bool local)
 		{ ScopedLock lock(mLock); mSIP.saveBYE(bye,local); }
 
+	bool sameINVITE(osip_message_t * msg)
+		{ ScopedLock lock(mLock); return mSIP.sameINVITE(msg); }
+
 	//@}
 
 	unsigned stateAge() const { ScopedLock lock(mLock); return mStateTimer.elapsed(); }
diff --git a/SIP/SIPEngine.cpp b/SIP/SIPEngine.cpp
index 42751aa..215c295 100644
--- a/SIP/SIPEngine.cpp
+++ b/SIP/SIPEngine.cpp
@@ -96,7 +96,7 @@ SIPEngine::SIPEngine(const char* proxy, const char* IMSI)
 	mSIPPort(gConfig.getNum("SIP.Local.Port")),
 	mSIPIP(gConfig.getStr("SIP.Local.IP")),
 	mINVITE(NULL), mLastResponse(NULL), mBYE(NULL),
-	mCANCEL(NULL), mUNAVAIL(NULL), mSession(NULL), 
+	mCANCEL(NULL), mERROR(NULL), mSession(NULL), 
 	mTxTime(0), mRxTime(0), mState(NullState),
 	mDTMF('\0'),mDTMFDuration(0)
 {
@@ -133,7 +133,7 @@ SIPEngine::~SIPEngine()
 	if (mLastResponse!=NULL) osip_message_free(mLastResponse);
 	if (mBYE!=NULL) osip_message_free(mBYE);
 	if (mCANCEL!=NULL) osip_message_free(mCANCEL);
-	if (mUNAVAIL!=NULL) osip_message_free(mUNAVAIL);
+	if (mERROR!=NULL) osip_message_free(mERROR);
 	// FIXME -- Do we need to dispose of the RtpSesion *mSesison?
 }
 
@@ -201,13 +201,13 @@ void SIPEngine::saveCANCEL(const osip_message_t *CANCEL, bool mine)
 	osip_message_clone(CANCEL,&mCANCEL);
 }
 
-void SIPEngine::saveUNAVAIL(const osip_message_t *UNAVAIL, bool mine)
+void SIPEngine::saveERROR(const osip_message_t *ERROR, bool mine)
 {
 	// Instead of cloning, why not just keep the old one?
 	// Because that doesn't work in all calling contexts.
 	// This simplifies the call-handling logic.
-	if (mUNAVAIL!=NULL) osip_message_free(mUNAVAIL);
-	osip_message_clone(UNAVAIL,&mUNAVAIL);
+	if (mERROR!=NULL) osip_message_free(mERROR);
+	osip_message_clone(ERROR,&mERROR);
 }
 
 /* we're going to figure if the from field is us or not */
@@ -578,17 +578,24 @@ SIPState SIPEngine::MODSendBYE()
 	return mState;
 }
 
-SIPState SIPEngine::MODSendUNAVAIL()
+SIPState SIPEngine::MODSendERROR(osip_message_t * cause, int code, const char * reason, bool cancel)
 {
 	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
-	assert(mINVITE);
-
-	osip_message_t * unavail = sip_temporarily_unavailable(mINVITE, mSIPIP.c_str(),
-							       mSIPUsername.c_str(), mSIPPort);
+	if (NULL == cause){
+		assert(mINVITE);
+		cause = mINVITE;
+	}
+	
+	/* 480 is unavail */
+	osip_message_t * unavail = sip_error(cause, mSIPIP.c_str(),
+					     mSIPUsername.c_str(), mSIPPort, 
+					     code, reason);
 	gSIPInterface.write(&mProxyAddr,unavail);
-	saveUNAVAIL(unavail, true);
+	saveERROR(unavail, true);
 	osip_message_free(unavail);
-	mState = MODCanceling;
+	if (cancel){
+		mState = MODCanceling;
+	}
 	return mState;
 }
 
@@ -625,12 +632,14 @@ SIPState SIPEngine::MODResendCANCEL()
 	return mState;
 }
 
-SIPState SIPEngine::MODResendUNAVAIL()
+SIPState SIPEngine::MODResendERROR(bool cancel)
 {
 	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
-	assert(mState==MODCanceling);
-	assert(mUNAVAIL);
-	gSIPInterface.write(&mProxyAddr,mUNAVAIL);
+	if (cancel){
+		if (mState!=MODCanceling) LOG(ERR) << "incorrect state for this method";
+	}
+	assert(mERROR);
+	gSIPInterface.write(&mProxyAddr,mERROR);
 	return mState;
 }
 
@@ -726,7 +735,7 @@ SIPState SIPEngine::MODWaitForCANCELOK()
 	return mState;
 }
 
-SIPState SIPEngine::MODWaitForUNAVAILACK()
+SIPState SIPEngine::MODWaitForERRORACK(bool cancel)
 {
 	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
 	bool responded = false;
@@ -737,20 +746,22 @@ SIPState SIPEngine::MODWaitForUNAVAILACK()
 			responded = true;
 			saveResponse(ack);
 			if ((NULL == ack->sip_method) || !strncmp(ack->sip_method,"ACK", 4)) {
-				LOG(WARNING) << "unexpected response to UNAVAIL, from proxy " << mProxyIP << ":" << mProxyPort << ". Assuming other end has cleared";
+				LOG(WARNING) << "unexpected response to ERROR, from proxy " << mProxyIP << ":" << mProxyPort << ". Assuming other end has cleared";
 			}
 			osip_message_free(ack);
 			break;
 		}
 		catch (SIPTimeout& e) {
-			LOG(NOTICE) << "response timeout, resending UNAVAIL";
-			MODResendUNAVAIL();
+			LOG(NOTICE) << "response timeout, resending ERROR";
+			MODResendERROR(cancel);
 		}
 	}
 
 	if (!responded) { LOG(ALERT) << "lost contact with proxy " << mProxyIP << ":" << mProxyPort; }
 
-	mState = Canceled;
+	if (cancel){
+		mState = Canceled;
+	}
 
 	return mState;
 }
@@ -1212,7 +1223,31 @@ bool SIPEngine::sendINFOAndWaitForOK(unsigned wInfo)
 
 };
 
-
-
+/* reinvite stuff */
+/* return true if this is the same invite as the one we have stored */
+bool SIPEngine::sameINVITE(osip_message_t * msg){
+	assert(mINVITE);
+	if (NULL == msg){
+		return false;
+	}
+	char* old_inv;
+	size_t old_len;
+	char* new_inv;
+	size_t new_len;
+	int res = 0; //does not match
+	//this sometimes fails even though mINVITE is real. No idea -k
+	osip_message_to_str(mINVITE, &old_inv, &old_len);
+	osip_message_to_str(msg, &new_inv, &new_len);
+	if (old_inv && new_inv){
+		res = !(strncmp(old_inv, new_inv, old_len));
+	}
+	if (old_inv){
+		free(old_inv);
+	}
+	if (new_inv){
+		free(new_inv);
+	}
+	return res;
+}
 
 // vim: ts=4 sw=4
diff --git a/SIP/SIPEngine.h b/SIP/SIPEngine.h
index 1933294..71c03ca 100644
--- a/SIP/SIPEngine.h
+++ b/SIP/SIPEngine.h
@@ -113,7 +113,7 @@ private:
 	//we should maybe push these together sometime? -kurtis
 	osip_message_t * mBYE;		///< the BYE message for this transaction
 	osip_message_t * mCANCEL;	///< the CANCEL message for this transaction
-	osip_message_t * mUNAVAIL;	///< the UNAVAIL message for this transaction
+	osip_message_t * mERROR;	///< the ERROR message for this transaction
 	//@}
 
 	/**@name RTP state and parameters. */
@@ -279,7 +279,7 @@ public:
 	//@{
 	SIPState MODSendBYE();
 
-	SIPState MODSendUNAVAIL();
+	SIPState MODSendERROR(osip_message_t * cause, int code, const char * reason, bool cancel);
 
 	SIPState MODSendCANCEL();
 
@@ -287,13 +287,13 @@ public:
 
 	SIPState MODResendCANCEL();
 
-	SIPState MODResendUNAVAIL();
+	SIPState MODResendERROR(bool cancel);
 
 	SIPState MODWaitForBYEOK();
 
 	SIPState MODWaitForCANCELOK();
 
-	SIPState MODWaitForUNAVAILACK();
+	SIPState MODWaitForERRORACK(bool cancel);
 
 	SIPState MODWaitFor487();
 	//@}
@@ -355,10 +355,12 @@ public:
 	/** Save a copy of a CANCEL message in the engine. */
 	void saveCANCEL(const osip_message_t *CANCEL, bool mine);
 
-	/** Save a copy of a UNAVAIL message in the engine. */
-	void saveUNAVAIL(const osip_message_t *UNAVAIL, bool mine);
-
+	/** Save a copy of a ERROR message in the engine. */
+	void saveERROR(const osip_message_t *ERROR, bool mine);
 
+	
+	/** Determine if this invite matches the saved one */
+	bool sameINVITE(osip_message_t * msg);
 
 	private:
 
diff --git a/SIP/SIPInterface.cpp b/SIP/SIPInterface.cpp
index 1f21edc..ba83e86 100644
--- a/SIP/SIPInterface.cpp
+++ b/SIP/SIPInterface.cpp
@@ -379,6 +379,15 @@ bool SIPInterface::checkInvite( osip_message_t * msg)
 			mSIPMap.remove(callIDNum);
 			return false;
 		}
+		//if this is not the saved invite, it's a RE-invite. Respond saying we don't support it. 
+		if (!transaction->sameINVITE(msg)){
+		  /* don't cancel the call */
+			transaction->MODSendERROR(msg, 488, "Not Acceptable Here", false);
+			/* I think we'd need to create a new transaction for this ack. Right now, just assume the ack makes it back. 
+			   if not, we'll hear another INVITE */
+			//transaction->MODWaitForERRORACK(false); //don't cancel the call
+			return false;
+		}
 		// There is transaction already.  Send trying.
 		transaction->MTCSendTrying();
 		// And if no channel is established yet, page again.
diff --git a/SIP/SIPMessage.cpp b/SIP/SIPMessage.cpp
index c700144..c475f4d 100644
--- a/SIP/SIPMessage.cpp
+++ b/SIP/SIPMessage.cpp
@@ -599,7 +599,7 @@ osip_message_t * SIP::sip_bye(const char * req_uri, const char * dialed_number,
 	return bye;
 }
 
-osip_message_t * SIP::sip_temporarily_unavailable( osip_message_t * invite,  const char * host, const char * username, short  port)
+osip_message_t * SIP::sip_error(osip_message_t * invite,  const char * host, const char * username, short port, short code, const char* reason)
 {
 
 	if(invite==NULL){ return NULL;}
@@ -610,8 +610,8 @@ osip_message_t * SIP::sip_temporarily_unavailable( osip_message_t * invite,  con
 	// FIXME -- Should use the "force_update" function.
 	unavail->message_property = 2;
 	//header stuff first
-	unavail->status_code = 480;
-	unavail->reason_phrase = strdup("Temporarily Unavailable");
+	unavail->status_code = code;
+	unavail->reason_phrase = strdup(reason);
 	osip_message_set_version(unavail, strdup("SIP/2.0"));
 
 	char local_port[10];
diff --git a/SIP/SIPMessage.h b/SIP/SIPMessage.h
index 81a9aa7..0f60751 100644
--- a/SIP/SIPMessage.h
+++ b/SIP/SIPMessage.h
@@ -55,7 +55,7 @@ osip_message_t * sip_okay_sdp( osip_message_t * inv, const char * sip_username,
 
 osip_message_t * sip_okay( osip_message_t * inv, const char * sip_username, const char * local_ip, short wlocal_port);
 
-osip_message_t * sip_temporarily_unavailable( osip_message_t * invite,  const char * host, const char * username, short  port);
+osip_message_t * sip_error( osip_message_t * invite,  const char * host, const char * username, short port, short code, const char* reason);
 
 osip_message_t * sip_info(unsigned info, const char *dialed_number, short rtp_port,const char * sip_username, short local_port, const char * local_ip, const char * proxy_ip, const char * from_tag, const char * via_branch, const osip_call_id_t* call_id_header, int cseq);
 
@@ -69,4 +69,3 @@ osip_message_t * sip_ringing( osip_message_t * invite, const char * sip_username
 
 };
 #endif
-