--- a/test-voice/rtp_tx.c	Mon Mar 11 12:45:09 2024 -0800
+++ b/test-voice/rtp_tx.c	Sun Apr 07 17:09:32 2024 -0800
@@ -20,11 +20,17 @@
 extern int rtp_udp_fd, rtcp_udp_fd, pcma_selected;
 extern struct timeval cur_event_time;
 
+static const uint8_t dmw_alaw[8] =
+	{0x34, 0x21, 0x21, 0x34, 0xB4, 0xA1, 0xA1, 0xB4};
+static const uint8_t dmw_ulaw[8] =
+	{0x1E, 0x0B, 0x0B, 0x1E, 0x9E, 0x8B, 0x8B, 0x9E};
+
 static uint32_t rtp_ssrc;
 static uint32_t rtp_out_ts;
 static uint16_t rtp_out_seq;
 
 static uint8_t pcm_fill_octet;
+static int dmw_active;
 
 static uint16_t tfo_fill_buf[9], tfo_req_buf[7];
 static uint16_t *is_out_ptr;
@@ -77,6 +83,23 @@
 	}
 }
 
+static void
+fill_with_dmw(buf)
+	uint8_t *buf;
+{
+	const uint8_t *src;
+	unsigned n;
+
+	if (pcma_selected)
+		src = dmw_alaw;
+	else
+		src = dmw_ulaw;
+	for (n = 0; n < 20; n++) {
+		memcpy(buf, src, 8);
+		buf += 8;
+	}
+}
+
 void
 generate_rtp_packet()
 {
@@ -89,7 +112,10 @@
 	pkt.tstamp = htonl(rtp_out_ts);
 	rtp_out_ts += 160;
 	pkt.ssrc = rtp_ssrc;
-	memset(pkt.payload, pcm_fill_octet, RTP_MAX_PAYLOAD);
+	if (dmw_active)
+		fill_with_dmw(pkt.payload);
+	else
+		memset(pkt.payload, pcm_fill_octet, RTP_MAX_PAYLOAD);
 	if (is_out_count) {
 		insert_is_msg(pkt.payload, *is_out_ptr++);
 		is_out_count--;
@@ -130,3 +156,15 @@
 {
 	tfo_stop_req = 1;
 }
+
+void
+cmd_dmw_on()
+{
+	dmw_active = 1;
+}
+
+void
+cmd_dmw_off()
+{
+	dmw_active = 0;
+}