Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 248348)
+++ channels/chan_sip.c	(working copy)
@@ -1064,6 +1064,7 @@
 	 * The large-scale changes would be a good idea for implementing during an SDP rewrite.
 	 */
 	struct offered_media offered_media[3];
+	struct ast_silence_generator *gen;
 } *iflist = NULL;
 
 /*! Max entires in the history list for a sip_pvt */
@@ -4030,8 +4031,12 @@
 		res = -1; /* Tell Asterisk to generate inband indications */
 		break;
 	case SIP_DTMF_RFC2833:
-		if (p->rtp)
+		if (p->rtp) {
+			if (ast_opt_transmit_silence) {
+				p->gen = ast_channel_start_silence_generator(ast);
+			}
 			ast_rtp_senddigit_begin(p->rtp, digit);
+		}
 		break;
 	default:
 		break;
@@ -4054,8 +4059,12 @@
 		transmit_info_with_digit(p, digit, duration);
 		break;
 	case SIP_DTMF_RFC2833:
-		if (p->rtp)
+		if (p->rtp) {
 			ast_rtp_senddigit_end(p->rtp, digit);
+			if (p->gen) {
+				ast_channel_stop_silence_generator(ast, p->gen);
+			}
+		}
 		break;
 	case SIP_DTMF_INBAND:
 		res = -1; /* Tell Asterisk to stop inband indications */
Index: main/rtp.c
===================================================================
--- main/rtp.c	(revision 248348)
+++ main/rtp.c	(working copy)
@@ -2707,7 +2707,7 @@
 		f->samples /= 2;
 	}
 
-	if (rtp->sending_digit) {
+	if (rtp->sending_digit && !ast_opt_transmit_silence) {
 		return 0;
 	}