diff --git a/CHANGES b/CHANGES
index 3b00468056fcaa5488de9fc0809ae45b3549fe55..49ad4d1e46fdbb73f053e891b6edfa5f0f69a703 100644
--- a/CHANGES
+++ b/CHANGES
@@ -347,6 +347,7 @@ libpri channel driver (chan_dahdi) DAHDI changes
  * Added the ability to support call waiting calls.  (The SETUP has no B channel
    assigned.)
  * Added Malicious Call ID (MCID) event to the AMI call event class.
+ * Added Message Waiting Indication (MWI) support for ISDN PTMP endpoints (phones).
 
 Asterisk Manager Interface
 --------------------------
diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index 17de19dcb1e16fbe29b97e365ba219aad1e940c9..af1b871f5349734c8448d4c8e249b656dcb784e6 100644
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -11895,6 +11895,11 @@ static struct dahdi_pvt *mkintf(int channel, const struct dahdi_chan_conf *conf,
 						pris[span].pri.aoce_delayhangup = conf->pri.pri.aoce_delayhangup;
 #endif	/* defined(HAVE_PRI_AOC_EVENTS) */
 						ast_copy_string(pris[span].pri.msn_list, conf->pri.pri.msn_list, sizeof(pris[span].pri.msn_list));
+#if defined(HAVE_PRI_MWI)
+						ast_copy_string(pris[span].pri.mwi_mailboxes,
+							conf->pri.pri.mwi_mailboxes,
+							sizeof(pris[span].pri.mwi_mailboxes));
+#endif	/* defined(HAVE_PRI_MWI) */
 						ast_copy_string(pris[span].pri.idledial, conf->pri.pri.idledial, sizeof(pris[span].pri.idledial));
 						ast_copy_string(pris[span].pri.idleext, conf->pri.pri.idleext, sizeof(pris[span].pri.idleext));
 						ast_copy_string(pris[span].pri.internationalprefix, conf->pri.pri.internationalprefix, sizeof(pris[span].pri.internationalprefix));
@@ -16586,6 +16591,7 @@ static int __unload_module(void)
 		for (j = 0; j < SIG_PRI_NUM_DCHANS; j++) {
 			dahdi_close_pri_fd(&(pris[i]), j);
 		}
+		sig_pri_stop_pri(&pris[i].pri);
 	}
 #if defined(HAVE_PRI_CCSS)
 	ast_cc_agent_unregister(&dahdi_pri_cc_agent_callbacks);
@@ -17450,6 +17456,11 @@ static int process_dahdi(struct dahdi_chan_conf *confp, const char *cat, struct
 			} else if (!strcasecmp(v->name, "allow_call_waiting_calls")) {
 				confp->pri.pri.allow_call_waiting_calls = ast_true(v->value);
 #endif	/* defined(HAVE_PRI_CALL_WAITING) */
+#if defined(HAVE_PRI_MWI)
+			} else if (!strcasecmp(v->name, "mwi_mailboxes")) {
+				ast_copy_string(confp->pri.pri.mwi_mailboxes, v->value,
+					sizeof(confp->pri.pri.mwi_mailboxes));
+#endif	/* defined(HAVE_PRI_MWI) */
 #endif /* HAVE_PRI */
 #ifdef HAVE_SS7
 			} else if (!strcasecmp(v->name, "ss7type")) {
diff --git a/channels/sig_pri.c b/channels/sig_pri.c
index 8955c670b79a72cf6c650e82e8250c0c35a938a4..8e7c73c22c13187d6115bb190de13ba744908eef 100644
--- a/channels/sig_pri.c
+++ b/channels/sig_pri.c
@@ -6423,6 +6423,130 @@ int sig_pri_digit_begin(struct sig_pri_chan *pvt, struct ast_channel *ast, char
 	return 1;
 }
 
+#if defined(HAVE_PRI_MWI)
+/*!
+ * \internal
+ * \brief Send a MWI indication to the given span.
+ * \since 1.8
+ *
+ * \param pri Asterisk D channel control structure.
+ * \param mbox_number Mailbox number
+ * \param mbox_context Mailbox context
+ * \param num_messages Number of messages waiting.
+ *
+ * \return Nothing
+ */
+static void sig_pri_send_mwi_indication(struct sig_pri_pri *pri, const char *mbox_number, const char *mbox_context, int num_messages)
+{
+	struct pri_party_id mailbox;
+
+	ast_debug(1, "Send MWI indication for %s@%s num_messages:%d\n", mbox_number,
+		mbox_context, num_messages);
+
+	memset(&mailbox, 0, sizeof(mailbox));
+	mailbox.number.valid = 1;
+	mailbox.number.presentation = PRES_ALLOWED_USER_NUMBER_NOT_SCREENED;
+	mailbox.number.plan = (PRI_TON_UNKNOWN << 4) | PRI_NPI_UNKNOWN;
+	ast_copy_string(mailbox.number.str, mbox_number, sizeof(mailbox.number.str));
+
+	ast_mutex_lock(&pri->lock);
+	pri_mwi_indicate(pri->pri, &mailbox, 1 /* speech */, num_messages, NULL, NULL, -1, 0);
+	ast_mutex_unlock(&pri->lock);
+}
+#endif	/* defined(HAVE_PRI_MWI) */
+
+#if defined(HAVE_PRI_MWI)
+/*!
+ * \internal
+ * \brief MWI subscription event callback.
+ * \since 1.8
+ *
+ * \param event the event being passed to the subscriber
+ * \param userdata the data provider in the call to ast_event_subscribe()
+ *
+ * \return Nothing
+ */
+static void sig_pri_mwi_event_cb(const struct ast_event *event, void *userdata)
+{
+	struct sig_pri_pri *pri = userdata;
+	const char *mbox_context;
+	const char *mbox_number;
+	int num_messages;
+
+	mbox_number = ast_event_get_ie_str(event, AST_EVENT_IE_MAILBOX);
+	if (ast_strlen_zero(mbox_number)) {
+		return;
+	}
+	mbox_context = ast_event_get_ie_str(event, AST_EVENT_IE_CONTEXT);
+	if (ast_strlen_zero(mbox_context)) {
+		return;
+	}
+	num_messages = ast_event_get_ie_uint(event, AST_EVENT_IE_NEWMSGS);
+	sig_pri_send_mwi_indication(pri, mbox_number, mbox_context, num_messages);
+}
+#endif	/* defined(HAVE_PRI_MWI) */
+
+#if defined(HAVE_PRI_MWI)
+/*!
+ * \internal
+ * \brief Send update MWI indications from the event cache.
+ * \since 1.8
+ *
+ * \param pri Asterisk D channel control structure.
+ *
+ * \return Nothing
+ */
+static void sig_pri_mwi_cache_update(struct sig_pri_pri *pri)
+{
+	int idx;
+	int num_messages;
+	struct ast_event *event;
+
+	for (idx = 0; idx < ARRAY_LEN(pri->mbox); ++idx) {
+		if (!pri->mbox[idx].sub) {
+			/* There are no more mailboxes on this span. */
+			break;
+		}
+
+		event = ast_event_get_cached(AST_EVENT_MWI,
+			AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, pri->mbox[idx].number,
+			AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, pri->mbox[idx].context,
+			AST_EVENT_IE_END);
+		if (!event) {
+			/* No cached event for this mailbox. */
+			continue;
+		}
+		num_messages = ast_event_get_ie_uint(event, AST_EVENT_IE_NEWMSGS);
+		sig_pri_send_mwi_indication(pri, pri->mbox[idx].number, pri->mbox[idx].context,
+			num_messages);
+		ast_event_destroy(event);
+	}
+}
+#endif	/* defined(HAVE_PRI_MWI) */
+
+/*!
+ * \brief Stop PRI span.
+ * \since 1.8
+ *
+ * \param pri Asterisk D channel control structure.
+ *
+ * \return Nothing
+ */
+void sig_pri_stop_pri(struct sig_pri_pri *pri)
+{
+#if defined(HAVE_PRI_MWI)
+	int idx;
+#endif	/* defined(HAVE_PRI_MWI) */
+
+#if defined(HAVE_PRI_MWI)
+	for (idx = 0; idx < ARRAY_LEN(pri->mbox); ++idx) {
+		if (pri->mbox[idx].sub) {
+			pri->mbox[idx].sub = ast_event_unsubscribe(pri->mbox[idx].sub);
+		}
+	}
+#endif	/* defined(HAVE_PRI_MWI) */
+}
+
 /*!
  * \internal
  * \brief qsort comparison function.
@@ -6477,11 +6601,72 @@ int sig_pri_start_pri(struct sig_pri_pri *pri)
 {
 	int x;
 	int i;
+#if defined(HAVE_PRI_MWI)
+	char *saveptr;
+	char *mbox_number;
+	char *mbox_context;
+	struct ast_str *mwi_description = ast_str_alloca(64);
+#endif	/* defined(HAVE_PRI_MWI) */
+
+#if defined(HAVE_PRI_MWI)
+	/* Prepare the mbox[] for use. */
+	for (i = 0; i < ARRAY_LEN(pri->mbox); ++i) {
+		if (pri->mbox[i].sub) {
+			pri->mbox[i].sub = ast_event_unsubscribe(pri->mbox[i].sub);
+		}
+	}
+#endif	/* defined(HAVE_PRI_MWI) */
 
 	ast_mutex_init(&pri->lock);
-
 	sig_pri_sort_pri_chans(pri);
 
+#if defined(HAVE_PRI_MWI)
+	/*
+	 * Split the mwi_mailboxes configuration string into the mbox[]:
+	 * mailbox_number[@context]{,mailbox_number[@context]}
+	 */
+	i = 0;
+	saveptr = pri->mwi_mailboxes;
+	while (i < ARRAY_LEN(pri->mbox)) {
+		mbox_number = strsep(&saveptr, ",");
+		if (!mbox_number) {
+			break;
+		}
+		/* Split the mailbox_number and context */
+		mbox_context = strchr(mbox_number, '@');
+		if (mbox_context) {
+			*mbox_context++ = '\0';
+			mbox_context = ast_strip(mbox_context);
+		}
+		mbox_number = ast_strip(mbox_number);
+		if (ast_strlen_zero(mbox_number)) {
+			/* There is no mailbox number.  Skip it. */
+			continue;
+		}
+		if (ast_strlen_zero(mbox_context)) {
+			/* There was no context so use the default. */
+			mbox_context = "default";
+		}
+
+		/* Fill the mbox[] element. */
+		ast_str_set(&mwi_description, -1, "%s span %d[%d] MWI mailbox %s@%s",
+			sig_pri_cc_type_name, pri->span, i, mbox_number, mbox_context);
+		pri->mbox[i].sub = ast_event_subscribe(AST_EVENT_MWI, sig_pri_mwi_event_cb,
+			ast_str_buffer(mwi_description), pri,
+			AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mbox_number,
+			AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, mbox_context,
+			AST_EVENT_IE_END);
+		if (!pri->mbox[i].sub) {
+			ast_log(LOG_ERROR, "%s span %d could not subscribe to MWI events for %s@%s.",
+				sig_pri_cc_type_name, pri->span, mbox_number, mbox_context);
+			continue;
+		}
+		pri->mbox[i].number = mbox_number;
+		pri->mbox[i].context = mbox_context;
+		++i;
+	}
+#endif	/* defined(HAVE_PRI_MWI) */
+
 	for (i = 0; i < SIG_PRI_NUM_DCHANS; i++) {
 		if (pri->fds[i] == -1) {
 			break;
@@ -6574,6 +6759,19 @@ int sig_pri_start_pri(struct sig_pri_pri *pri)
 		ast_log(LOG_ERROR, "Unable to spawn D-channel: %s\n", strerror(errno));
 		return -1;
 	}
+
+#if defined(HAVE_PRI_MWI)
+	/*
+	 * Send the initial MWI indications from the event cache for this span.
+	 *
+	 * If we were loaded after app_voicemail the event would already be in
+	 * the cache.  If we were loaded before app_voicemail the event would not
+	 * be in the cache yet and app_voicemail will send the event when it
+	 * gets loaded.
+	 */
+	sig_pri_mwi_cache_update(pri);
+#endif	/* defined(HAVE_PRI_MWI) */
+
 	return 0;
 }
 
diff --git a/channels/sig_pri.h b/channels/sig_pri.h
index 450a36eec91f39b503fe84b0f2a63dd68ac47e10..e7f424f5fd50f17c7f3f9ce06eceef4a93a275ab 100644
--- a/channels/sig_pri.h
+++ b/channels/sig_pri.h
@@ -27,6 +27,7 @@
 
 #include "asterisk/channel.h"
 #include "asterisk/frame.h"
+#include "asterisk/event.h"
 #include "asterisk/ccss.h"
 #include <libpri.h>
 #include <dahdi/user.h>
@@ -251,6 +252,35 @@ struct sig_pri_chan {
 #endif
 };
 
+#if defined(HAVE_PRI_MWI)
+/*! Maximum number of mailboxes per span. */
+#define SIG_PRI_MAX_MWI_MAILBOXES			8
+/*! Typical maximum length of mwi mailbox number */
+#define SIG_PRI_MAX_MWI_MBOX_NUMBER_LEN		10	/* digits in number */
+/*! Typical maximum length of mwi mailbox context */
+#define SIG_PRI_MAX_MWI_CONTEXT_LEN			10
+/*!
+ * \brief Maximum mwi_mailbox string length.
+ * \details
+ * max_length = #mailboxes * (mbox_number + '@' + context + ',')
+ * The last ',' is a null terminator instead.
+ */
+#define SIG_PRI_MAX_MWI_MAILBOX_STR		(SIG_PRI_MAX_MWI_MAILBOXES	\
+	* (SIG_PRI_MAX_MWI_MBOX_NUMBER_LEN + 1 + SIG_PRI_MAX_MWI_CONTEXT_LEN + 1))
+
+struct sig_pri_mbox {
+	/*!
+	 * \brief MWI mailbox event subscription.
+	 * \note NULL if mailbox not configured.
+	 */
+	struct ast_event_sub *sub;
+	/*! \brief Mailbox number */
+	const char *number;
+	/*! \brief Mailbox context. */
+	const char *context;
+};
+#endif	/* defined(HAVE_PRI_MWI) */
+
 struct sig_pri_pri {
 	/* Should be set by user */
 	struct ast_cc_config_params *cc_params;			/*!< CC config parameters for each new call. */
@@ -294,6 +324,17 @@ struct sig_pri_pri {
 	char privateprefix[20];					/*!< for private dialplans */
 	char unknownprefix[20];					/*!< for unknown dialplans */
 	long resetinterval;						/*!< Interval (in seconds) for resetting unused channels */
+#if defined(HAVE_PRI_MWI)
+	/*! \brief Active MWI mailboxes */
+	struct sig_pri_mbox mbox[SIG_PRI_MAX_MWI_MAILBOXES];
+	/*!
+	 * \brief Comma separated list of mailboxes to indicate MWI.
+	 * \note Empty if disabled.
+	 * \note Format: mailbox_number[@context]{,mailbox_number[@context]}
+	 * \note String is split apart when span is started.
+	 */
+	char mwi_mailboxes[SIG_PRI_MAX_MWI_MAILBOX_STR];
+#endif	/* defined(HAVE_PRI_MWI) */
 	char msn_list[AST_MAX_EXTENSION];		/*!< Comma separated list of MSNs to handle.  Empty if disabled. */
 	char idleext[AST_MAX_EXTENSION];		/*!< Where to idle extra calls */
 	char idlecontext[AST_MAX_CONTEXT];		/*!< What context to use for idle */
@@ -412,6 +453,7 @@ void sig_pri_init_pri(struct sig_pri_pri *pri);
  * functions should handle it normally (generate inband DTMF) */
 int sig_pri_digit_begin(struct sig_pri_chan *pvt, struct ast_channel *ast, char digit);
 
+void sig_pri_stop_pri(struct sig_pri_pri *pri);
 int sig_pri_start_pri(struct sig_pri_pri *pri);
 
 void sig_pri_chan_alarm_notify(struct sig_pri_chan *p, int noalarm);
diff --git a/configs/chan_dahdi.conf.sample b/configs/chan_dahdi.conf.sample
index 157deca28d29421c7c41b6bc06b49368dd6bac52..0187555b44a49663241e943532bb5724900c15b5 100644
--- a/configs/chan_dahdi.conf.sample
+++ b/configs/chan_dahdi.conf.sample
@@ -526,6 +526,12 @@ callwaiting=yes
 ; A call waiting call is a SETUP message with no B channel selected.
 ;allow_call_waiting_calls=no
 ;
+; Configure the ISDN span to indicate MWI for the list of mailboxes.
+; You can give a comma separated list of up to 8 mailboxes per span.
+; An empty list disables MWI.
+; The default is an empty list.
+;mwi_mailboxes=mailbox_number[@context]{,mailbox_number[@context]}
+;
 ; Whether or not restrict outgoing caller ID (will be sent as ANI only, not
 ; available for the user)
 ; Mostly use with FXS ports
diff --git a/configure b/configure
index 124d6c840ef6ad73d3924f0ab5df5c1b71e3d2d5..f9ae50ba55ff7cb439db27a62574ac3c59342297 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 267261 .
+# From configure.ac Revision: 267350 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.63 for asterisk 1.6.
 #
@@ -874,6 +874,10 @@ PBX_PRI_MCID
 PRI_MCID_DIR
 PRI_MCID_INCLUDE
 PRI_MCID_LIB
+PBX_PRI_MWI
+PRI_MWI_DIR
+PRI_MWI_INCLUDE
+PRI_MWI_LIB
 PBX_PRI
 PRI_DIR
 PRI_INCLUDE
@@ -10097,6 +10101,25 @@ fi
 
 
 
+PRI_MWI_DESCRIP="ISDN PRI Message Waiting Indication"
+PRI_MWI_OPTION=pri
+
+for i in ${ac_mandatory_list}; do
+   if test "xPRI" = "x$i"; then
+      ac_mandatory_list="${ac_mandatory_list} PRI_MWI"
+      break
+   fi
+done
+
+PBX_PRI_MWI=0
+
+
+
+
+
+
+
+
 PRI_MCID_DESCRIP="ISDN PRI Malicious Call ID"
 PRI_MCID_OPTION=pri
 
@@ -35531,6 +35554,273 @@ fi
 
 
 
+if test "x${PBX_PRI_MWI}" != "x1" -a "${USE_PRI_MWI}" != "no"; then
+   pbxlibdir=""
+   # if --with-PRI_MWI=DIR has been specified, use it.
+   if test "x${PRI_MWI_DIR}" != "x"; then
+      if test -d ${PRI_MWI_DIR}/lib; then
+      	 pbxlibdir="-L${PRI_MWI_DIR}/lib"
+      else
+      	 pbxlibdir="-L${PRI_MWI_DIR}"
+      fi
+   fi
+   pbxfuncname="pri_mwi_indicate"
+   if test "x${pbxfuncname}" = "x" ; then   # empty lib, assume only headers
+      AST_PRI_MWI_FOUND=yes
+   else
+      ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
+      CFLAGS="${CFLAGS} "
+      as_ac_Lib=`$as_echo "ac_cv_lib_pri_${pbxfuncname}" | $as_tr_sh`
+{ $as_echo "$as_me:$LINENO: checking for ${pbxfuncname} in -lpri" >&5
+$as_echo_n "checking for ${pbxfuncname} in -lpri... " >&6; }
+if { as_var=$as_ac_Lib; eval "test \"\${$as_var+set}\" = set"; }; then
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpri ${pbxlibdir}  $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char ${pbxfuncname} ();
+int
+main ()
+{
+return ${pbxfuncname} ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext && {
+	 test "$cross_compiling" = yes ||
+	 $as_test_x conftest$ac_exeext
+       }; then
+  eval "$as_ac_Lib=yes"
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	eval "$as_ac_Lib=no"
+fi
+
+rm -rf conftest.dSYM
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+ac_res=`eval 'as_val=${'$as_ac_Lib'}
+		 $as_echo "$as_val"'`
+	       { $as_echo "$as_me:$LINENO: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+as_val=`eval 'as_val=${'$as_ac_Lib'}
+		 $as_echo "$as_val"'`
+   if test "x$as_val" = x""yes; then
+  AST_PRI_MWI_FOUND=yes
+else
+  AST_PRI_MWI_FOUND=no
+fi
+
+      CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
+   fi
+
+   # now check for the header.
+   if test "${AST_PRI_MWI_FOUND}" = "yes"; then
+      PRI_MWI_LIB="${pbxlibdir} -lpri "
+      # if --with-PRI_MWI=DIR has been specified, use it.
+      if test "x${PRI_MWI_DIR}" != "x"; then
+         PRI_MWI_INCLUDE="-I${PRI_MWI_DIR}/include"
+      fi
+      PRI_MWI_INCLUDE="${PRI_MWI_INCLUDE} "
+      if test "xlibpri.h" = "x" ; then	# no header, assume found
+         PRI_MWI_HEADER_FOUND="1"
+      else				# check for the header
+         ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
+         CPPFLAGS="${CPPFLAGS} ${PRI_MWI_INCLUDE}"
+         if test "${ac_cv_header_libpri_h+set}" = set; then
+  { $as_echo "$as_me:$LINENO: checking for libpri.h" >&5
+$as_echo_n "checking for libpri.h... " >&6; }
+if test "${ac_cv_header_libpri_h+set}" = set; then
+  $as_echo_n "(cached) " >&6
+fi
+{ $as_echo "$as_me:$LINENO: result: $ac_cv_header_libpri_h" >&5
+$as_echo "$ac_cv_header_libpri_h" >&6; }
+else
+  # Is the header compilable?
+{ $as_echo "$as_me:$LINENO: checking libpri.h usability" >&5
+$as_echo_n "checking libpri.h usability... " >&6; }
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+$ac_includes_default
+#include <libpri.h>
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  ac_header_compiler=yes
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_header_compiler=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+{ $as_echo "$as_me:$LINENO: result: $ac_header_compiler" >&5
+$as_echo "$ac_header_compiler" >&6; }
+
+# Is the header present?
+{ $as_echo "$as_me:$LINENO: checking libpri.h presence" >&5
+$as_echo_n "checking libpri.h presence... " >&6; }
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <libpri.h>
+_ACEOF
+if { (ac_try="$ac_cpp conftest.$ac_ext"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_cpp conftest.$ac_ext") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } >/dev/null && {
+	 test -z "$ac_c_preproc_warn_flag$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       }; then
+  ac_header_preproc=yes
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+  ac_header_preproc=no
+fi
+
+rm -f conftest.err conftest.$ac_ext
+{ $as_echo "$as_me:$LINENO: result: $ac_header_preproc" >&5
+$as_echo "$ac_header_preproc" >&6; }
+
+# So?  What about this header?
+case $ac_header_compiler:$ac_header_preproc:$ac_c_preproc_warn_flag in
+  yes:no: )
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: accepted by the compiler, rejected by the preprocessor!" >&5
+$as_echo "$as_me: WARNING: libpri.h: accepted by the compiler, rejected by the preprocessor!" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: proceeding with the compiler's result" >&5
+$as_echo "$as_me: WARNING: libpri.h: proceeding with the compiler's result" >&2;}
+    ac_header_preproc=yes
+    ;;
+  no:yes:* )
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: present but cannot be compiled" >&5
+$as_echo "$as_me: WARNING: libpri.h: present but cannot be compiled" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h:     check for missing prerequisite headers?" >&5
+$as_echo "$as_me: WARNING: libpri.h:     check for missing prerequisite headers?" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: see the Autoconf documentation" >&5
+$as_echo "$as_me: WARNING: libpri.h: see the Autoconf documentation" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h:     section \"Present But Cannot Be Compiled\"" >&5
+$as_echo "$as_me: WARNING: libpri.h:     section \"Present But Cannot Be Compiled\"" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: proceeding with the preprocessor's result" >&5
+$as_echo "$as_me: WARNING: libpri.h: proceeding with the preprocessor's result" >&2;}
+    { $as_echo "$as_me:$LINENO: WARNING: libpri.h: in the future, the compiler will take precedence" >&5
+$as_echo "$as_me: WARNING: libpri.h: in the future, the compiler will take precedence" >&2;}
+    ( cat <<\_ASBOX
+## ------------------------------- ##
+## Report this to www.asterisk.org ##
+## ------------------------------- ##
+_ASBOX
+     ) | sed "s/^/$as_me: WARNING:     /" >&2
+    ;;
+esac
+{ $as_echo "$as_me:$LINENO: checking for libpri.h" >&5
+$as_echo_n "checking for libpri.h... " >&6; }
+if test "${ac_cv_header_libpri_h+set}" = set; then
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_header_libpri_h=$ac_header_preproc
+fi
+{ $as_echo "$as_me:$LINENO: result: $ac_cv_header_libpri_h" >&5
+$as_echo "$ac_cv_header_libpri_h" >&6; }
+
+fi
+if test "x$ac_cv_header_libpri_h" = x""yes; then
+  PRI_MWI_HEADER_FOUND=1
+else
+  PRI_MWI_HEADER_FOUND=0
+fi
+
+
+         CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
+      fi
+      if test "x${PRI_MWI_HEADER_FOUND}" = "x0" ; then
+         PRI_MWI_LIB=""
+         PRI_MWI_INCLUDE=""
+      else
+         if test "x${pbxfuncname}" = "x" ; then		# only checking headers -> no library
+            PRI_MWI_LIB=""
+         fi
+         PBX_PRI_MWI=1
+         cat >>confdefs.h <<_ACEOF
+#define HAVE_PRI_MWI 1
+_ACEOF
+
+      fi
+   fi
+fi
+
+
+
 if test "x${PBX_PRI_MCID}" != "x1" -a "${USE_PRI_MCID}" != "no"; then
    pbxlibdir=""
    # if --with-PRI_MCID=DIR has been specified, use it.
diff --git a/configure.ac b/configure.ac
index f5ac507e0f9bda71b4e14ed2a722988cf83c4e71..a7dd8dce8bd23a45fbe184115c738675a5dc3f14 100644
--- a/configure.ac
+++ b/configure.ac
@@ -341,6 +341,7 @@ AST_EXT_LIB_SETUP([PGSQL], [PostgreSQL], [postgres])
 AST_EXT_LIB_SETUP([POPT], [popt], [popt])
 AST_EXT_LIB_SETUP([PORTAUDIO], [PortAudio], [portaudio])
 AST_EXT_LIB_SETUP([PRI], [ISDN PRI], [pri])
+AST_EXT_LIB_SETUP_DEPENDENT([PRI_MWI], [ISDN PRI Message Waiting Indication], [PRI], [pri])
 AST_EXT_LIB_SETUP_DEPENDENT([PRI_MCID], [ISDN PRI Malicious Call ID], [PRI], [pri])
 AST_EXT_LIB_SETUP_DEPENDENT([PRI_CALL_WAITING], [ISDN PRI call waiting supplementary service], [PRI], [pri])
 AST_EXT_LIB_SETUP_DEPENDENT([PRI_AOC_EVENTS], [ISDN PRI advice of charge supplementary service events], [PRI], [pri])
@@ -1594,6 +1595,7 @@ AST_EXT_LIB_CHECK([POPT], [popt], [poptStrerror], [popt.h])
 AST_EXT_LIB_CHECK([PORTAUDIO], [portaudio], [Pa_GetDeviceCount], [portaudio.h])
 
 AST_EXT_LIB_CHECK([PRI], [pri], [pri_connected_line_update], [libpri.h])
+AST_EXT_LIB_CHECK([PRI_MWI], [pri], [pri_mwi_indicate], [libpri.h])
 AST_EXT_LIB_CHECK([PRI_MCID], [pri], [pri_mcid_enable], [libpri.h])
 AST_EXT_LIB_CHECK([PRI_CALL_WAITING], [pri], [pri_connect_ack_enable], [libpri.h])
 AST_EXT_LIB_CHECK([PRI_AOC_EVENTS], [pri], [pri_aoc_events_enable], [libpri.h])
diff --git a/include/asterisk/autoconfig.h.in b/include/asterisk/autoconfig.h.in
index a97017a60a1916f964e0d1dbebdb5a3160a087f9..97b6c4b121e2826f39b98924f7cfc9cd7f9c0380 100644
--- a/include/asterisk/autoconfig.h.in
+++ b/include/asterisk/autoconfig.h.in
@@ -560,6 +560,9 @@
 /* Define to 1 if you have the ISDN PRI Malicious Call ID library. */
 #undef HAVE_PRI_MCID
 
+/* Define to 1 if you have the ISDN PRI Message Waiting Indication library. */
+#undef HAVE_PRI_MWI
+
 /* Define to 1 if you have the ISDN progress with cause library. */
 #undef HAVE_PRI_PROG_W_CAUSE