diff --git a/libpri.h b/libpri.h
index 9d39fef..b7fd5bf 100755
--- a/libpri.h
+++ b/libpri.h
@@ -93,6 +93,7 @@
 #define PRI_PROG_INTERWORKING_NO_RELEASE				(1 << 6)
 #define PRI_PROG_INTERWORKING_NO_RELEASE_PRE_ANSWER		(1 << 7)
 #define PRI_PROG_INTERWORKING_NO_RELEASE_POST_ANSWER	(1 << 8)
+#define PRI_PROG_CALLER_RETURNED_TO_ISDN					(1 << 9)
 
 /* Numbering plan identifier */
 #define PRI_NPI_UNKNOWN					0x0
diff --git a/q931.c b/q931.c
index 5b383b4..a5eb761 100755
--- a/q931.c
+++ b/q931.c
@@ -183,6 +183,7 @@ struct msgtype facilities[] = {
 #define Q931_PROG_CALL_NOT_E2E_ISDN						0x01
 #define Q931_PROG_CALLED_NOT_ISDN						0x02
 #define Q931_PROG_CALLER_NOT_ISDN						0x03
+#define Q931_PROG_CALLER_RETURNED_TO_ISDN					0x04
 #define Q931_PROG_INBAND_AVAILABLE						0x08
 #define Q931_PROG_DELAY_AT_INTERF						0x0a
 #define Q931_PROG_INTERWORKING_WITH_PUBLIC				0x10
@@ -1048,6 +1049,9 @@ static FUNC_RECV(receive_progress_indicator)
 	case Q931_PROG_CALLER_NOT_ISDN:
 		call->progressmask |= PRI_PROG_CALLER_NOT_ISDN;
 		break;
+	case Q931_PROG_CALLER_RETURNED_TO_ISDN:
+		call->progressmask |= PRI_PROG_CALLER_RETURNED_TO_ISDN;
+		break;
 	case Q931_PROG_INBAND_AVAILABLE:
 		call->progressmask |= PRI_PROG_INBAND_AVAILABLE;
 		break;