diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 14ca33276b..802a31ce3c 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -4154,7 +4154,7 @@ static struct ast_channel *sip_new(struct sip_pvt *i, int state, const char *tit
 
 
 
-	if (ast_test_flag(&i->flags[0], SIP_DTMF) ==  SIP_DTMF_INBAND) {
+	if ((ast_test_flag(&i->flags[0], SIP_DTMF) == SIP_DTMF_INBAND) || (ast_test_flag(&i->flags[0], SIP_DTMF) == SIP_DTMF_AUTO)) {
 		i->vad = ast_dsp_new();
 		ast_dsp_set_features(i->vad, DSP_FEATURE_DTMF_DETECT);
 		if (global_relaxdtmf)