diff --git a/asterisk/IMS_ConnectionHandler.ttcn b/asterisk/IMS_ConnectionHandler.ttcn
index a55935a..a253c9f 100644
--- a/asterisk/IMS_ConnectionHandler.ttcn
+++ b/asterisk/IMS_ConnectionHandler.ttcn
@@ -388,8 +388,8 @@
 	var template (present) PDU_SIP_Request exp_req :=
 		tr_SIP_REGISTER(g_pars.registrar_sip_req_uri,
 				?,
-				tr_SipAddr(),
-				tr_SipAddr(),
+				tr_From(),
+				tr_To(),
 				tr_Via_from(?),
 				require := tr_Require(superset("sec-agree")),
 				security_client := tr_Security_client(superset(tr_Security_mechanism("ipsec-3gpp",
@@ -402,8 +402,8 @@
 		var Via via;
 		var CallidString sip_call_id;
 		var Contact contact;
-		var template (value) SipAddr from_addr;
-		var template (value) SipAddr to_addr;
+		var template (value) From from_addr;
+		var template (value) To to_addr;
 		var template (value) CommaParam_List digestCln ;
 		var template (value) WwwAuthenticate wwwAuthenticate;
 		var template (value) P_Associated_Uri p_associated_uri := ts_P_Associated_Uri({});
@@ -418,10 +418,8 @@
 		sip_call_id := g_rx_sip_req.msgHeader.callId.callid;
 		via := g_rx_sip_req.msgHeader.via;
 		via.viaBody[0].viaParams := f_sip_param_set(via.viaBody[0].viaParams, "rport", "1234"); /* TODO: set remote src port of the REGISTER */
-		from_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.fromField.addressField,
-							g_rx_sip_req.msgHeader.fromField.fromParams);
-		to_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.toField.addressField,
-						      g_rx_sip_req.msgHeader.toField.toParams);
+		from_addr := g_rx_sip_req.msgHeader.fromField;
+		to_addr := g_rx_sip_req.msgHeader.toField;
 		sip_seq_nr := g_rx_sip_req.msgHeader.cSeq.seqNumber;
 
 		contact := g_rx_sip_req.msgHeader.contact;
@@ -455,7 +453,7 @@
 		f_ims_parse_security_client(g_rx_sip_req.msgHeader.security_client);
 		f_ims_setup_ipsec();
 
-		to_addr.params := f_sip_param_set(to_addr.params, "tag", f_sip_rand_tag());
+		to_addr.toParams := f_sip_param_set(to_addr.toParams, "tag", f_sip_rand_tag());
 
 		digestCln := {
 			ts_Param("realm", f_sip_str_quote(g_pars.realm)),
@@ -512,18 +510,16 @@
 		exp_req :=
 		tr_SIP_REGISTER(g_pars.registrar_sip_req_uri,
 				?,
-				tr_SipAddr(),
-				tr_SipAddr(),
+				tr_From(),
+				tr_To(),
 				tr_Via_from(?),
 				authorization := authorization);
 		SIP.receive(exp_req) -> value g_rx_sip_req;
 
 		sip_call_id := g_rx_sip_req.msgHeader.callId.callid;
 		via := g_rx_sip_req.msgHeader.via;
-		from_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.fromField.addressField,
-							g_rx_sip_req.msgHeader.fromField.fromParams);
-		to_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.toField.addressField,
-						      g_rx_sip_req.msgHeader.toField.toParams);
+		from_addr := g_rx_sip_req.msgHeader.fromField;
+		to_addr := g_rx_sip_req.msgHeader.toField;
 		sip_seq_nr := g_rx_sip_req.msgHeader.cSeq.seqNumber;
 
 		/* Tx 100 Trying */
@@ -552,7 +548,7 @@
 			});
 
 		/* Tx 200 OK */
-		to_addr.params := f_sip_param_set(to_addr.params, "tag", f_sip_rand_tag());
+		to_addr.toParams := f_sip_param_set(to_addr.toParams, "tag", f_sip_rand_tag());
 		tx_resp := ts_SIP_Response(sip_call_id,
 			from_addr,
 			to_addr,
diff --git a/asterisk/SIP_ConnectionHandler.ttcn b/asterisk/SIP_ConnectionHandler.ttcn
index 9c7cca5..41a29e4 100644
--- a/asterisk/SIP_ConnectionHandler.ttcn
+++ b/asterisk/SIP_ConnectionHandler.ttcn
@@ -80,8 +80,8 @@
 	SipAddr calling optional,
 	SipAddr called optional,
 
-	SipAddr from_addr optional,
-	SipAddr to_addr optional,
+	From from_addr optional,
+	To to_addr optional,
 
 	CallidString sip_call_id,
 	integer sip_seq_nr,
@@ -263,7 +263,9 @@
 	var template (present) PDU_SIP_Response exp;
 	var Authorization authorization;
 	var Via via := g_pars.local_via;
-	var SipAddr from_sipaddr := g_pars.registrar_sip_record;
+	var From from_addr := valueof(ts_From(g_pars.registrar_sip_record.addr, g_pars.registrar_sip_record.params));
+	var To to_addr := valueof(ts_To(g_pars.registrar_sip_record.addr, g_pars.registrar_sip_record.params));
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(to_addr.addressField), *);
 	var charstring branch_value;
 
 	branch_value := f_sip_gen_branch(f_sip_SipAddr_to_str(g_pars.registrar_sip_record),
@@ -272,11 +274,11 @@
 					 g_pars.registrar_sip_seq_nr);
 
 	via.viaBody[0].viaParams := f_sip_param_set(via.viaBody[0].viaParams, "branch", branch_value);
-	from_sipaddr.params := f_sip_param_set(from_sipaddr.params, "tag", f_sip_rand_tag());
+	from_addr.fromParams := f_sip_param_set(from_addr.fromParams, "tag", f_sip_rand_tag());
 	SIP.send(ts_SIP_REGISTER(g_pars.registrar_sip_req_uri,
 				 g_pars.registrar_sip_call_id,
-				 from_sipaddr,
-				 g_pars.registrar_sip_record,
+				 from_addr,
+				 to_addr,
 				 via,
 				 g_pars.registrar_sip_seq_nr,
 				 g_pars.local_contact,
@@ -284,8 +286,8 @@
 
 	exp := tr_SIP_Response_Unauthorized(
 			g_pars.registrar_sip_call_id,
-			from_sipaddr,
-			f_tr_To_response(g_pars.registrar_sip_record),
+			from_addr,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			*,
 			tr_WwwAuthenticate({tr_Challenge_digestCln(?)}),
@@ -308,8 +310,8 @@
 
 	SIP.send(ts_SIP_REGISTER(g_pars.registrar_sip_req_uri,
 				g_pars.registrar_sip_call_id,
-				from_sipaddr,
-				g_pars.registrar_sip_record,
+				from_addr,
+				to_addr,
 				via,
 				g_pars.registrar_sip_seq_nr,
 				g_pars.local_contact,
@@ -319,8 +321,8 @@
 	/* Wait for OK answer */
 	exp := tr_SIP_Response(
 			g_pars.registrar_sip_call_id,
-			from_sipaddr,
-			f_tr_To_response(g_pars.registrar_sip_record),
+			from_addr,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			*,
 			"REGISTER", 200,
@@ -336,17 +338,21 @@
 {
 	var template (value) PDU_SIP_Request req;
 	var template (present) PDU_SIP_Response exp;
+	var template (present) From from_addr_exp;
+	var template (present) To to_addr_exp;
 	var Via via;
 	var charstring tx_sdp := f_gen_sdp();
 	var default d_trying, d_ringing;
 	var charstring branch_value;
 
 	/* RFC 3261 8.1.1.3 From */
-	g_pars.cp.from_addr := g_pars.cp.calling;
-	g_pars.cp.from_addr.params := f_sip_param_set(g_pars.cp.from_addr.params, "tag", f_sip_rand_tag());
-	g_pars.cp.to_addr := g_pars.cp.called;
-	branch_value := f_sip_gen_branch(f_sip_SipAddr_to_str(g_pars.cp.from_addr),
-					 f_sip_SipAddr_to_str(valueof(g_pars.cp.to_addr)),
+	g_pars.cp.from_addr := valueof(ts_From(g_pars.cp.calling.addr, g_pars.cp.calling.params));
+	g_pars.cp.from_addr.fromParams := f_sip_param_set(g_pars.cp.from_addr.fromParams, "tag", f_sip_rand_tag());
+	g_pars.cp.to_addr := valueof(ts_To(g_pars.cp.called.addr, g_pars.cp.called.params));
+	from_addr_exp := tr_From(tr_Addr_Union_from_val(g_pars.cp.from_addr.addressField), *);
+	to_addr_exp := tr_To(tr_Addr_Union_from_val(g_pars.cp.to_addr.addressField), *);
+	branch_value := f_sip_gen_branch(f_sip_Addr_Union_to_str(g_pars.cp.from_addr.addressField),
+					 f_sip_Addr_Union_to_str(valueof(g_pars.cp.to_addr.addressField)),
 					 g_pars.cp.sip_call_id,
 					 g_pars.cp.sip_seq_nr);
 	via := g_pars.local_via;
@@ -365,8 +371,8 @@
 	/* RFC 3261 22.2: */
 	exp := tr_SIP_Response_Unauthorized(
 			g_pars.cp.sip_call_id,
-			f_tr_From(g_pars.cp.from_addr),
-			f_tr_To_response(g_pars.cp.to_addr),
+			from_addr_exp,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			*,
 			tr_WwwAuthenticate({tr_Challenge_digestCln(?)}),
@@ -385,16 +391,16 @@
 
 	/* Conditionally match and accept 100 Trying. */
 	exp := tr_SIP_Response_Trying(g_pars.cp.sip_call_id,
-			g_pars.cp.from_addr,
-			f_tr_To_response(g_pars.cp.to_addr),
+			from_addr_exp,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			g_pars.cp.sip_seq_nr, "INVITE");
 	d_trying := activate(as_SIP_ignore_resp(exp));
 
 	/* Conditionally match and accept 180 Ringing */
 	exp := tr_SIP_Response_Ringing(g_pars.cp.sip_call_id,
-			g_pars.cp.from_addr,
-			f_tr_To_response(g_pars.cp.to_addr),
+			from_addr_exp,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			g_pars.cp.sip_seq_nr, "INVITE");
 	d_ringing := activate(as_SIP_ignore_resp(exp));
@@ -402,8 +408,8 @@
 	/* Wait for OK answer */
 	exp := tr_SIP_Response(
 			g_pars.cp.sip_call_id,
-			g_pars.cp.from_addr,
-			f_tr_To_response(g_pars.cp.to_addr),
+			from_addr_exp,
+			to_addr_exp,
 			f_tr_Via_response(via),
 			*,
 			"INVITE", 200,
@@ -415,8 +421,7 @@
 	deactivate(d_ringing);
 
 	/* Update To with the tags received from peer: */
-	g_pars.cp.to_addr := valueof(ts_SipAddr_from_Addr_Union(g_rx_sip_resp.msgHeader.toField.addressField,
-								g_rx_sip_resp.msgHeader.toField.toParams));
+	g_pars.cp.to_addr := g_rx_sip_resp.msgHeader.toField;
 
 	/* Transmit ACK */
 	g_pars.cp.sip_seq_nr := g_pars.cp.sip_seq_nr + 1;
@@ -437,11 +442,9 @@
 
 	/* Obtain params: */
 	g_pars.cp.sip_call_id := rx_sip_req.msgHeader.callId.callid;
-	g_pars.cp.from_addr := valueof(ts_SipAddr_from_Addr_Union(rx_sip_req.msgHeader.fromField.addressField,
-								rx_sip_req.msgHeader.fromField.fromParams));
-	g_pars.cp.to_addr := valueof(ts_SipAddr_from_Addr_Union(rx_sip_req.msgHeader.toField.addressField,
-								rx_sip_req.msgHeader.toField.toParams));
-	g_pars.cp.to_addr.params := f_sip_param_set(g_pars.cp.to_addr.params, "tag", f_sip_rand_tag());
+	g_pars.cp.from_addr := rx_sip_req.msgHeader.fromField;
+	g_pars.cp.to_addr := rx_sip_req.msgHeader.toField;
+	g_pars.cp.to_addr.toParams := f_sip_param_set(g_pars.cp.to_addr.toParams, "tag", f_sip_rand_tag());
 	g_pars.cp.sip_seq_nr := rx_sip_req.msgHeader.cSeq.seqNumber;
 }
 
@@ -452,8 +455,8 @@
 	var template (present) PDU_SIP_Request exp_req :=
 		tr_SIP_INVITE(f_tr_SipUrl_opt_defport(g_pars.local_sip_url_ext),
 			      ?,
-			      f_tr_From(g_pars.cp.calling),
-			      g_pars.cp.called,
+			      tr_From(tr_Addr_Union_from_val(g_pars.cp.calling.addr), *),
+			      tr_To(tr_Addr_Union_from_val(g_pars.cp.called.addr), *),
 			      tr_Via_from(f_tr_HostPort(g_pars.remote_sip_host, g_pars.remote_sip_port)),
 			      ?, ?);
 	var charstring sip_expect_str := log2str(exp_req);
@@ -518,8 +521,8 @@
 	var template (present) PDU_SIP_Request exp_req :=
 		tr_SIP_INVITE(f_tr_SipUrl_opt_defport(g_pars.local_sip_url_ext),
 			      ?,
-			      f_tr_From(g_pars.cp.calling),
-			      g_pars.cp.called,
+			      tr_From(tr_Addr_Union_from_val(g_pars.cp.calling.addr), *),
+			      tr_To(tr_Addr_Union_from_val(g_pars.cp.called.addr), *),
 			      tr_Via_from(f_tr_HostPort(g_pars.remote_sip_host, g_pars.remote_sip_port)),
 			      ?, ?);
 	var charstring sip_expect_str := log2str(exp_req);
@@ -527,7 +530,7 @@
 	[] SIP.receive(exp_req) -> value g_rx_sip_req {
 		var template (value) PDU_SIP_Response tx_resp;
 		var Via via;
-		var template (present) SipAddr exp_to_addr;
+		var template (present) To exp_to_addr;
 		var charstring tx_sdp;
 
 		/* Obtain params: */
@@ -550,8 +553,7 @@
 		/* Wait for CANCEL */
 		/* Cancel may come even before we send Ringing, hence To's "tag"
 		 * may not be known by peer, so g_pars.to_addr can't be used here: */
-		exp_to_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.toField.addressField,
-							  g_rx_sip_req.msgHeader.toField.toParams);
+		exp_to_addr := g_rx_sip_req.msgHeader.toField;
 		exp_req := tr_SIP_CANCEL(f_tr_SipUrl_opt_defport(g_pars.local_sip_url_ext),
 					 g_pars.cp.sip_call_id,
 					 g_pars.cp.from_addr,
@@ -636,8 +638,8 @@
 	var Via via;
 	var charstring branch_value;
 
-	branch_value := f_sip_gen_branch(f_sip_SipAddr_to_str(g_pars.cp.from_addr),
-					 f_sip_SipAddr_to_str(valueof(g_pars.cp.to_addr)),
+	branch_value := f_sip_gen_branch(f_sip_Addr_Union_to_str(g_pars.cp.from_addr.addressField),
+					 f_sip_Addr_Union_to_str(valueof(g_pars.cp.to_addr.addressField)),
 					 g_pars.cp.sip_call_id,
 					 g_pars.cp.sip_seq_nr);
 
@@ -657,7 +659,7 @@
 	exp_resp := tr_SIP_Response(
 			g_pars.cp.sip_call_id,
 			g_pars.cp.from_addr,
-			f_tr_To_response(g_pars.cp.to_addr),
+			tr_To(tr_Addr_Union_from_val(g_pars.cp.to_addr.addressField), *),
 			f_tr_Via_response(via),
 			*,
 			"BYE", 200,
diff --git a/library/SIP_Templates.ttcn b/library/SIP_Templates.ttcn
index 72a4426..9f45b9f 100644
--- a/library/SIP_Templates.ttcn
+++ b/library/SIP_Templates.ttcn
@@ -227,6 +227,20 @@
 	deltaSec := deltaSec
 }
 
+// [20.20]
+template (value) From ts_From(template (value) Addr_Union addressField,
+			      template (omit) SemicolonParam_List fromParams := omit) := {
+	fieldName := FROM_E,
+	addressField := addressField,
+	fromParams := fromParams
+}
+template (present) From tr_From(template (present) Addr_Union addressField := ?,
+			        template SemicolonParam_List fromParams := *) := {
+	fieldName := FROM_E,
+	addressField := addressField,
+	fromParams := fromParams
+}
+
 // [RFC3455 5.4] + 3GPP 24.229 V8.7.0
 template (present) Access_net_spec tr_Access_net_spec(template (present) charstring access_type := ?,
 						      template SemicolonParam_List access_info := *) := {
@@ -296,6 +310,20 @@
 	optionsTags := optionsTags
 }
 
+// [20.39]
+template (value) To ts_To(template (value) Addr_Union addressField,
+			  template (omit) SemicolonParam_List toParams := omit) := {
+	fieldName := TO_E,
+	addressField := addressField,
+	toParams := toParams
+}
+template (present) To tr_To(template (present) Addr_Union addressField := ?,
+			    template SemicolonParam_List toParams := *) := {
+	fieldName := TO_E,
+	addressField := addressField,
+	toParams := toParams
+}
+
 // [20.41 RFC2616 14.43]
 template (value) UserAgent ts_UserAgent(template (value) ServerVal_List userAgentBody := {}) := {
 	fieldName := USER_AGENT_E,
@@ -347,17 +375,24 @@
 
 	return ret;
 }
+function tr_Addr_Union_from_val(template (value) Addr_Union tin) return template (present) Addr_Union {
+	var template (present) Addr_Union ret := tin;
+
+	if (not ispresent(tin.nameAddr.displayName)) {
+		ret.nameAddr.displayName := *;
+	} else if (f_str_tolower(f_sip_str_unquote(tin.nameAddr.displayName)) == "anonymous") {
+		/* if the user is Anonymous, it may be omitted */
+		ret.nameAddr.displayName := tin.nameAddr.displayName ifpresent;
+	}
+
+	ret.nameAddr.addrSpec := tr_SipUrl_from_val(tin.nameAddr.addrSpec);
+
+	return ret;
+}
 function tr_SipAddr_from_val(template (value) SipAddr tin) return template (present) SipAddr {
 	var template (present) SipAddr ret := tin;
 
-	if (not ispresent(tin.addr.nameAddr.displayName)) {
-		ret.addr.nameAddr.displayName := *;
-	} else if (f_str_tolower(f_sip_str_unquote(tin.addr.nameAddr.displayName)) == "anonymous") {
-		/* if the user is Anonymous, it may be omitted */
-		ret.addr.nameAddr.displayName := tin.addr.nameAddr.displayName ifpresent;
-	}
-
-	ret.addr.nameAddr.addrSpec := tr_SipUrl_from_val(tin.addr.nameAddr.addrSpec);
+	ret.addr := tr_Addr_Union_from_val(tin.addr);
 
 	if (not ispresent(tin.params)) {
 		ret.params := *;
@@ -601,8 +636,8 @@
 template (value) MessageHeader ts_SIP_msgHeader_empty := c_SIP_msgHeader_empty;
 template (value) MessageHeader
 ts_SIP_msgh_std(template (value) CallidString call_id,
-		template (value) SipAddr from_addr,
-		template (value) SipAddr to_addr,
+		template (value) From from_addr,
+		template (value) To to_addr,
 		template (omit) Contact contact,
 		template (value) charstring method,
 		template (value) integer seq_nr,
@@ -636,22 +671,14 @@
 		method := method
 	},
 	expires := expires,
-	fromField := {
-		fieldName := FROM_E,
-		addressField := from_addr.addr,
-		fromParams := from_addr.params
-	},
+	fromField := from_addr,
 	p_associated_uri := p_associated_uri,
 	require := require,
 	security_client := security_client,
 	security_server := security_server,
 	server := server,
 	supported := supported,
-	toField := {
-		fieldName := TO_E,
-		addressField := to_addr.addr,
-		toParams := to_addr.params
-	},
+	toField := to_addr,
 	userAgent := userAgent,
 	via := via,
 	wwwAuthenticate := wwwAuthenticate
@@ -659,8 +686,8 @@
 
 template (present) MessageHeader
 tr_SIP_msgh_std(template CallidString call_id,
-		template SipAddr from_addr,
-		template SipAddr to_addr,
+		template From from_addr,
+		template To to_addr,
 		template Contact contact,
 		template (present) Via via := tr_Via_from(?),
 		template charstring method,
@@ -694,22 +721,14 @@
 		method := method
 	},
 	expires := expires,
-	fromField := {
-		fieldName := FROM_E,
-		addressField := from_addr.addr,
-		fromParams := from_addr.params
-	},
+	fromField := from_addr,
 	p_associated_uri := p_associated_uri,
 	require := require,
 	security_client := security_client,
 	security_server := security_server,
 	server := server,
 	supported := supported,
-	toField := {
-		fieldName := TO_E,
-		addressField := to_addr.addr,
-		toParams := to_addr.params
-	},
+	toField := to_addr,
 	userAgent := userAgent,
 	via := via,
 	wwwAuthenticate := wwwAuthenticate
@@ -719,8 +738,8 @@
 template (value) PDU_SIP_Request
 ts_SIP_REGISTER(template (value) SipUrl sip_url_host_port,
 		template (value) CallidString call_id,
-		template (value) SipAddr from_addr,
-		template (value) SipAddr to_addr,
+		template (value) From from_addr,
+		template (value) To to_addr,
 		template (value) Via via,
 		integer seq_nr,
 		template (omit) Contact contact,
@@ -746,8 +765,8 @@
 template (present) PDU_SIP_Request
 tr_SIP_REGISTER(template (present) SipUrl sip_url_host_port := ?,
 		template (present) CallidString call_id := ?,
-		template (present) SipAddr from_addr := ?,
-		template (present) SipAddr to_addr := ?,
+		template (present) From from_addr := ?,
+		template (present) To to_addr := ?,
 		template (present) Via via := tr_Via_from(f_tr_HostPort_opt_defport(?)),
 		template integer seq_nr := *,
 		template Authorization authorization := *,
@@ -771,13 +790,13 @@
 
 template (value) PDU_SIP_Request
 ts_SIP_INVITE(template (value) CallidString call_id,
-	      template (value) SipAddr from_addr,
-	      template (value) SipAddr to_addr,
+	      template (value) From from_addr,
+	      template (value) To to_addr,
 	      template (value) Via via,
 	      template (value) Contact contact,
 	      integer seq_nr,
 	      template (omit) charstring body := omit) := {
-	requestLine := ts_SIP_ReqLine(INVITE_E, to_addr.addr.nameAddr.addrSpec),
+	requestLine := ts_SIP_ReqLine(INVITE_E, to_addr.addressField.nameAddr.addrSpec),
 	msgHeader := ts_SIP_msgh_std(call_id, from_addr, to_addr, contact,
 				     "INVITE", seq_nr,
 				     via,
@@ -789,8 +808,8 @@
 template (present) PDU_SIP_Request
 tr_SIP_INVITE(template (present) SipUrl uri,
 	      template CallidString call_id,
-	      template SipAddr from_addr,
-	      template SipAddr to_addr,
+	      template From from_addr,
+	      template To to_addr,
 	      template Via via := tr_Via_from(f_tr_HostPort_opt_defport(?)),
 	      template integer seq_nr,
 	      template charstring body) := {
@@ -803,12 +822,12 @@
 
 template (value) PDU_SIP_Request
 ts_SIP_BYE(CallidString call_id,
-	   template (value) SipAddr from_addr,
-	   template (value) SipAddr to_addr,
+	   template (value) From from_addr,
+	   template (value) To to_addr,
 	   template (value) Via via,
 	   integer seq_nr,
 	   template (omit) charstring body) := {
-	requestLine := ts_SIP_ReqLine(BYE_E, to_addr.addr.nameAddr.addrSpec),
+	requestLine := ts_SIP_ReqLine(BYE_E, to_addr.addressField.nameAddr.addrSpec),
 	msgHeader := ts_SIP_msgh_std(call_id, from_addr, to_addr, omit, "BYE", seq_nr,
 				     via,
 				     content_length := f_ContentLength(body),
@@ -820,8 +839,8 @@
 template (present) PDU_SIP_Request
 tr_SIP_BYE(template (present) SipUrl uri,
 	   template CallidString call_id,
-	   template SipAddr from_addr,
-	   template SipAddr to_addr,
+	   template From from_addr,
+	   template To to_addr,
 	   template Via via,
 	   template integer seq_nr,
 	   template charstring body := *) := {
@@ -835,14 +854,14 @@
 
 template (value) PDU_SIP_Request
 ts_SIP_ACK(template (value) CallidString call_id,
-	   template (value) SipAddr from_addr,
-	   template (value) SipAddr to_addr,
+	   template (value) From from_addr,
+	   template (value) To to_addr,
 	   template (value) Via via,
 	   integer seq_nr,
 	   template (omit) charstring body) := {
-	requestLine := ts_SIP_ReqLine(ACK_E, to_addr.addr.nameAddr.addrSpec),
+	requestLine := ts_SIP_ReqLine(ACK_E, to_addr.addressField.nameAddr.addrSpec),
 	msgHeader := ts_SIP_msgh_std(call_id, from_addr, to_addr,
-				     ts_Contact_SipAddr(from_addr),
+				     ts_Contact({ ts_ContactAddress(from_addr.addressField, from_addr.fromParams) }),
 				     "ACK", seq_nr,
 				     via,
 				     content_length := f_ContentLength(body),
@@ -853,8 +872,8 @@
 template (present) PDU_SIP_Request
 tr_SIP_ACK(template (present) SipUrl uri,
 	   template CallidString call_id,
-	   template SipAddr from_addr,
-	   template SipAddr to_addr,
+	   template From from_addr,
+	   template To to_addr,
 	   template Via via,
 	   template integer seq_nr,
 	   template charstring body) := {
@@ -869,8 +888,8 @@
 template (present) PDU_SIP_Request
 tr_SIP_CANCEL(template (present) SipUrl uri,
 	      template (present) CallidString call_id,
-	      template (present) SipAddr from_addr,
-	      template (present) SipAddr to_addr,
+	      template (present) From from_addr,
+	      template (present) To to_addr,
 	      template (present) Via via,
 	      template (present) integer seq_nr,
 	      template charstring body := *) := {
@@ -884,8 +903,8 @@
 
 template (value) PDU_SIP_Response
 ts_SIP_Response(template (value) CallidString call_id,
-		template (value) SipAddr from_addr,
-		template (value) SipAddr to_addr,
+		template (value) From from_addr,
+		template (value) To to_addr,
 		charstring method,
 		integer status_code,
 		integer seq_nr,
@@ -916,8 +935,8 @@
 template (value) PDU_SIP_Response
 ts_SIP_Response_Trying(
 	template (value) CallidString call_id,
-	template (value) SipAddr from_addr,
-	template (value) SipAddr to_addr,
+	template (value) From from_addr,
+	template (value) To to_addr,
 	Via via,
 	integer seq_nr,
 	charstring method := "INVITE",
@@ -940,8 +959,8 @@
 template (value) PDU_SIP_Response
 ts_SIP_Response_Ringing(
 	template (value) CallidString call_id,
-	template (value) SipAddr from_addr,
-	template (value) SipAddr to_addr,
+	template (value) From from_addr,
+	template (value) To to_addr,
 	Via via,
 	integer seq_nr,
 	charstring method := "INVITE",
@@ -959,8 +978,8 @@
 template (value) PDU_SIP_Response
 ts_SIP_Response_Unauthorized(
 	template (value) CallidString call_id,
-	template (value) SipAddr from_addr,
-	template (value) SipAddr to_addr,
+	template (value) From from_addr,
+	template (value) To to_addr,
 	Via via,
 	template (value) WwwAuthenticate wwwAuthenticate,
 	integer seq_nr,
@@ -990,8 +1009,8 @@
 
 template (present) PDU_SIP_Response
 tr_SIP_Response(template CallidString call_id,
-		template SipAddr from_addr,
-		template SipAddr to_addr,
+		template From from_addr,
+		template To to_addr,
 		template (present) Via via := tr_Via_from(?),
 		template Contact contact,
 		template charstring method,
@@ -1011,8 +1030,8 @@
 template (present) PDU_SIP_Response
 tr_SIP_Response_Unauthorized(
 	template CallidString call_id,
-	template SipAddr from_addr,
-	template SipAddr to_addr,
+	template From from_addr,
+	template To to_addr,
 	template (present) Via via := tr_Via_from(?),
 	template Contact contact := *,
 	template (present) WwwAuthenticate wwwAuthenticate := ?,
@@ -1034,8 +1053,8 @@
 template (present) PDU_SIP_Response
 tr_SIP_Response_Trying(
 	template CallidString call_id,
-	template SipAddr from_addr,
-	template SipAddr to_addr,
+	template From from_addr,
+	template To to_addr,
 	template (present) Via via := tr_Via_from(?),
 	template integer seq_nr := ?,
 	template charstring method := "INVITE",
@@ -1054,8 +1073,8 @@
 template (present) PDU_SIP_Response
 tr_SIP_Response_Ringing(
 	template CallidString call_id,
-	template SipAddr from_addr,
-	template SipAddr to_addr,
+	template From from_addr,
+	template To to_addr,
 	template (present) Via via := tr_Via_from(?),
 	template integer seq_nr := ?,
 	template charstring method := "INVITE",
@@ -1474,12 +1493,16 @@
 	}
 }
 
-function f_sip_SipAddr_to_str(SipAddr sip_addr) return charstring {
-	if (ischosen(sip_addr.addr.nameAddr)) {
-		return f_sip_NameAddr_to_str(sip_addr.addr.nameAddr);
+function f_sip_Addr_Union_to_str(Addr_Union addru) return charstring {
+	if (ischosen(addru.nameAddr)) {
+		return f_sip_NameAddr_to_str(addru.nameAddr);
 	} else {
-		return f_sip_SipUrl_to_str(sip_addr.addr.addrSpecUnion);
+		return f_sip_SipUrl_to_str(addru.addrSpecUnion);
 	}
 }
 
+function f_sip_SipAddr_to_str(SipAddr sip_addr) return charstring {
+	return f_sip_Addr_Union_to_str(sip_addr.addr);
+}
+
 }
diff --git a/sip/SIP_Tests.ttcn b/sip/SIP_Tests.ttcn
index 84ddcb5..9c376f3 100644
--- a/sip/SIP_Tests.ttcn
+++ b/sip/SIP_Tests.ttcn
@@ -231,8 +231,12 @@
 
 /* Establish a mobile terminated call described in 'cp' */
 function f_establish_mt(inout CallPars cp) runs on ConnHdlr {
-	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
-	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var template (value) From from_addr := ts_From(cp.comp.sip_url_ext.addr, cp.comp.sip_url_ext.params);
+	var template (value) To to_addr := ts_To(cp.comp.sip_url_gsm.addr, cp.comp.sip_url_gsm.params);
+	var template (value) Via via := ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort);
+	var template (present) From from_addr_exp := tr_From(tr_Addr_Union_from_val(cp.comp.sip_url_ext.addr), *);
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(cp.comp.sip_url_gsm.addr), *);
+	var template (present) Via via_exp := tr_Via_from(f_tr_HostPort_opt_defport(from_addr_exp.addressField.nameAddr.addrSpec.hostPort));
 	var MNCC_PDU mncc;
 
 	/* The last SDP that the MSC received via MNCC from osmo-sip-connector */
@@ -266,8 +270,8 @@
 	f_create_mncc_expect(cp.called);
 
 	/* OSC <- SIP: A party sends SIP invite for a MT-call into OSC */
-	SIP.send(ts_SIP_INVITE(cp.comp.sip_call_id, cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
-			       ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort),
+	SIP.send(ts_SIP_INVITE(cp.comp.sip_call_id, from_addr, to_addr,
+			       via,
 			       ts_Contact_SipAddr(cp.comp.sip_url_ext),
 			       cp.comp.sip_seq_nr, cp.comp.sip_body));
 	if (cp.mncc_with_sdp) {
@@ -276,8 +280,8 @@
 	}
 
 	/* OSC -> SIP */
-	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm,
-					   tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_ext.addr.nameAddr.addrSpec.hostPort)),
+	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, from_addr_exp, to_addr_exp,
+					   via_exp,
 					   *,
 					   "INVITE", 100, ?, "Trying", *));
 
@@ -291,8 +295,8 @@
 	[] SIP.receive {
 		setverdict(fail, "Received unexpected SIP response");
 		SIP.send(ts_SIP_ACK(cp.comp.sip_call_id,
-				    cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
-				    ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort),
+				    from_addr, to_addr,
+				    via,
 				    cp.comp.sip_seq_nr, omit));
 		mtc.stop;
 		}
@@ -334,8 +338,8 @@
 	SIP.clear;
 
 	/* 180 Ringing should not contain any SDP. */
-	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm,
-					   tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_ext.addr.nameAddr.addrSpec.hostPort)),
+	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, from_addr_exp, to_addr_exp,
+					   via_exp,
 					   *,
 					   "INVITE", 180, ?, "Ringing", omit));
 
@@ -350,8 +354,8 @@
 	}
 
 	/* OSC -> SIP: OSC confirms call establishment to SIP side */
-	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm,
-					   tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_ext.addr.nameAddr.addrSpec.hostPort)),
+	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, from_addr_exp, to_addr_exp,
+					   via_exp,
 					   contact := ?,
 					   method := "INVITE", status_code := 200,
 					   seq_nr := ?, reason := "OK",
@@ -359,8 +363,8 @@
 
 	/* OSC <- SIP: SIP world acknowledges "200 OK" */
 	SIP.send(ts_SIP_ACK(cp.comp.sip_call_id,
-			    cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
-			    ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort),
+			    from_addr, to_addr,
+			    via,
 			    cp.comp.sip_seq_nr, omit));
 	/* MSC <- OSC: OSC sends SETUP COMPL to MNCC (which triggers CC CONNECT ACK */
 	MNCC.receive(tr_MNCC_SETUP_COMPL_req(cp.mncc_call_id)) -> value mncc {
@@ -372,8 +376,15 @@
 function f_establish_mo(inout CallPars cp) runs on ConnHdlr {
 	var MNCC_number dst := valueof(ts_MNCC_number(cp.called, GSM48_TON_UNKNOWN));
 	var MNCC_number src := valueof(ts_MNCC_number(cp.calling, GSM48_TON_UNKNOWN));
-	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
-	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+
+	var template (value) From from_addr := ts_From(cp.comp.sip_url_gsm.addr, cp.comp.sip_url_gsm.params);
+	var template (value) To to_addr := ts_To(cp.comp.sip_url_ext.addr, cp.comp.sip_url_ext.params);
+	var template (value) Via via := ts_Via_from(cp.comp.sip_url_gsm.addr.nameAddr.addrSpec.hostPort);
+	var template (present) From from_addr_exp := tr_From(tr_Addr_Union_from_val(cp.comp.sip_url_gsm.addr), *);
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(cp.comp.sip_url_ext.addr), *);
+	var template (present) Via via_exp := tr_Via_from(f_tr_HostPort_opt_defport(from_addr_exp.addressField.nameAddr.addrSpec.hostPort));
+
+
 	var PDU_SIP_Request sip_req;
 	var integer seq_nr;
 	var MNCC_PDU mncc;
@@ -436,16 +447,16 @@
 		 * "a=sendrecv;" */
 		expect_sdp_to_sip := pattern cn_sdp & "*";
 	}
-	sip_req := f_SIP_expect_req(tr_SIP_INVITE(sip_addr_ext.addr.nameAddr.addrSpec, ?,
-						  sip_addr_gsm, sip_addr_ext,
-						  tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_gsm.addr.nameAddr.addrSpec.hostPort)),
+	sip_req := f_SIP_expect_req(tr_SIP_INVITE(to_addr_exp.addressField.nameAddr.addrSpec, ?,
+						  from_addr_exp, to_addr_exp,
+						  via_exp,
 						  ?, expect_sdp_to_sip));
-	cp.comp.sip_url_gsm.params := sip_req.msgHeader.fromField.fromParams;
+	from_addr.fromParams := sip_req.msgHeader.fromField.fromParams;
 	cp.comp.sip_call_id := sip_req.msgHeader.callId.callid;
 	seq_nr := sip_req.msgHeader.cSeq.seqNumber;
 
 	/* OSC <- SIP: Notify call is proceeding */
-	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, from_addr, to_addr,
 				 "INVITE", 100, seq_nr, "Trying", sip_req.msgHeader.via));
 	/* MSC <- OSC: "100 Trying" translated to MNCC_CALL_PROC_REQ */
 	MNCC.receive(tr_MNCC_CALL_PROC_req(cp.mncc_call_id)) -> value mncc {
@@ -453,7 +464,7 @@
 	}
 
 	/* OSC <- SIP: SIP-terminated user is ringing now. 180 Ringing should not contain any SDP. */
-	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, from_addr, to_addr,
 				 "INVITE", 180, seq_nr, "Ringing", sip_req.msgHeader.via, omit));
 
 	/* MSC <- OSC: "180 Ringing" translated to MNCC_ALERT_REQ */
@@ -462,7 +473,7 @@
 	}
 
 	/* OSC <- SIP: SIP-terminated user has accepted the call */
-	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, from_addr, to_addr,
 				 "INVITE", 200, seq_nr, "OK", sip_req.msgHeader.via,
 				 body := cp.comp.sip_body));
 
@@ -483,32 +494,36 @@
 	/* MSC -> OSC: CC CONNECT ACK was received from MS */
 	MNCC.send(ts_MNCC_SETUP_COMPL_ind(cp.mncc_call_id));
 	/* OSC -> SIP: Acknowledge the call */
-	SIP.receive(tr_SIP_ACK(sip_addr_ext.addr.nameAddr.addrSpec,
+	SIP.receive(tr_SIP_ACK(to_addr_exp.addressField.nameAddr.addrSpec,
 			       cp.comp.sip_call_id,
-			       sip_addr_gsm,
-			       sip_addr_ext,
-			       tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_gsm.addr.nameAddr.addrSpec.hostPort)),
+			       from_addr_exp,
+			       to_addr_exp,
+			       via_exp,
 			       ?, omit));
 }
 
 /* Release call from the mobile side */
 function f_release_mobile(inout CallPars cp) runs on ConnHdlr {
-	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
-	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var template (value) From from_addr := ts_From(cp.comp.sip_url_gsm.addr, cp.comp.sip_url_gsm.params);
+	var template (value) To to_addr := ts_To(cp.comp.sip_url_ext.addr, cp.comp.sip_url_ext.params);
+	var template (value) Via via := ts_Via_from(cp.comp.sip_url_gsm.addr.nameAddr.addrSpec.hostPort);
+	var template (present) From from_addr_exp := tr_From(tr_Addr_Union_from_val(cp.comp.sip_url_gsm.addr), *);
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(cp.comp.sip_url_ext.addr), *);
+	var template (present) Via via_exp := tr_Via_from(f_tr_HostPort_opt_defport(from_addr_exp.addressField.nameAddr.addrSpec.hostPort));
 	var PDU_SIP_Request sip_req;
 	SIP.clear;
 	/* MSC -> OSC: Simulate a CC DISCONNET from the MT user */
 	MNCC.send(ts_MNCC_DISC_ind(cp.mncc_call_id, ts_MNCC_cause(0)));
 
 	/* OSC -> SIP: Expect BYE from OSC to SIP side */
-	sip_req := f_SIP_expect_req(tr_SIP_BYE(sip_addr_ext.addr.nameAddr.addrSpec,
-					       cp.comp.sip_call_id, sip_addr_gsm, sip_addr_ext,
-					       tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_gsm.addr.nameAddr.addrSpec.hostPort)),
+	sip_req := f_SIP_expect_req(tr_SIP_BYE(to_addr_exp.addressField.nameAddr.addrSpec,
+					       cp.comp.sip_call_id, from_addr_exp, to_addr_exp,
+					       via_exp,
 					       ?, *));
-	cp.comp.sip_url_gsm.params := sip_req.msgHeader.fromField.fromParams;
+	from_addr.fromParams := sip_req.msgHeader.fromField.fromParams;
 
 	/* OSC <- SIP: Acknowledge the BYE */
-	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, cp.comp.sip_url_gsm, cp.comp.sip_url_ext,
+	SIP.send(ts_SIP_Response(cp.comp.sip_call_id, from_addr, to_addr,
 					 "BYE", 200, sip_req.msgHeader.cSeq.seqNumber, "OK",
 					 sip_req.msgHeader.via));
 	/* MSC <- OSC: Send REL_REQ to MSC, triggers CC RELEASE REQ to MS */
@@ -519,19 +534,23 @@
 
 /* Release call from the SIP side */
 function f_release_sip(inout CallPars cp) runs on ConnHdlr {
-	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
-	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var template (value) From from_addr := ts_From(cp.comp.sip_url_ext.addr, cp.comp.sip_url_ext.params);
+	var template (value) To to_addr := ts_To(cp.comp.sip_url_gsm.addr, cp.comp.sip_url_gsm.params);
+	var template (value) Via via := ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort);
+	var template (present) From from_addr_exp := tr_From(tr_Addr_Union_from_val(cp.comp.sip_url_ext.addr), *);
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(cp.comp.sip_url_gsm.addr), *);
+	var template (present) Via via_exp := tr_Via_from(f_tr_HostPort_opt_defport(from_addr_exp.addressField.nameAddr.addrSpec.hostPort));
 	/* OSC <- SIP: SIP-side sends a BYE to OSC */
-	SIP.send(ts_SIP_BYE(cp.comp.sip_call_id, cp.comp.sip_url_ext, cp.comp.sip_url_gsm,
-			    ts_Via_from(cp.comp.sip_url_ext.addr.nameAddr.addrSpec.hostPort),
+	SIP.send(ts_SIP_BYE(cp.comp.sip_call_id, from_addr, to_addr,
+			    via,
 			    cp.comp.sip_seq_nr, omit));
 	/* MSC <- OSC: Expect OSC to cause MNCC Disconnect Request */
 	MNCC.receive(tr_MNCC_DISC_req(cp.mncc_call_id));
 	/* MSC -> OSC: Indicate GSM side release */
 	MNCC.send(ts_MNCC_REL_ind(cp.mncc_call_id, ts_MNCC_cause(0)));
 	/* OSC -> SIP: Confirmation to SIP side */
-	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, sip_addr_ext, sip_addr_gsm,
-					   tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_ext.addr.nameAddr.addrSpec.hostPort)),
+	as_SIP_expect_resp(tr_SIP_Response(cp.comp.sip_call_id, from_addr_exp, to_addr_exp,
+					   via_exp,
 					   *,
 					   "BYE", 200, cp.comp.sip_seq_nr, "OK", omit));
 }
@@ -675,8 +694,12 @@
 
 	var MNCC_number dst := valueof(ts_MNCC_number(cp.called, GSM48_TON_UNKNOWN));
 	var MNCC_number src := valueof(ts_MNCC_number(cp.calling, GSM48_TON_UNKNOWN));
-	var template SipAddr sip_addr_gsm := tr_SipAddr_from_val(cp.comp.sip_url_gsm);
-	var template SipAddr sip_addr_ext := tr_SipAddr_from_val(cp.comp.sip_url_ext);
+	var template (value) From from_addr := ts_From(cp.comp.sip_url_gsm.addr, cp.comp.sip_url_gsm.params);
+	var template (value) To to_addr := ts_To(cp.comp.sip_url_ext.addr, cp.comp.sip_url_ext.params);
+	var template (value) Via via := ts_Via_from(cp.comp.sip_url_gsm.addr.nameAddr.addrSpec.hostPort);
+	var template (present) From from_addr_exp := tr_From(tr_Addr_Union_from_val(cp.comp.sip_url_gsm.addr), *);
+	var template (present) To to_addr_exp := tr_To(tr_Addr_Union_from_val(cp.comp.sip_url_ext.addr), *);
+	var template (present) Via via_exp := tr_Via_from(f_tr_HostPort_opt_defport(from_addr_exp.addressField.nameAddr.addrSpec.hostPort));
 
 	f_create_sip_expect(cp.comp.sip_url_ext.addr.nameAddr.addrSpec);
 
@@ -700,9 +723,9 @@
 	timer T := 10.0;
 	T.start;
 	alt {
-	[] SIP.receive(tr_SIP_INVITE(sip_addr_ext.addr.nameAddr.addrSpec, ?,
-				     sip_addr_gsm, sip_addr_ext,
-				     tr_Via_from(f_tr_HostPort_opt_defport(sip_addr_gsm.addr.nameAddr.addrSpec.hostPort)),
+	[] SIP.receive(tr_SIP_INVITE(to_addr_exp.addressField.nameAddr.addrSpec, ?,
+				     from_addr_exp, to_addr_exp,
+				     via_exp,
 				     ?, ?)) {
 		setverdict(fail, "Received unexpected INVITE");
 		}