diff --git a/apps/asterisk/configmap.yaml b/apps/asterisk/configmap.yaml
index 8005fd9..b682949 100644
--- a/apps/asterisk/configmap.yaml
+++ b/apps/asterisk/configmap.yaml
@@ -96,7 +96,7 @@ data:
     allow=ulaw
     allow=alaw
     direct_media=no
-    dtmf_mode=auto
+    dtmf_mode=inband
     rtp_symmetric=yes
     force_rport=yes
     rewrite_contact=yes