diff --git a/libs/freetdm/src/ozmod/ozmod_wanpipe/ozmod_wanpipe.c b/libs/freetdm/src/ozmod/ozmod_wanpipe/ozmod_wanpipe.c
index cb9f28f971..afabfb0a0f 100644
--- a/libs/freetdm/src/ozmod/ozmod_wanpipe/ozmod_wanpipe.c
+++ b/libs/freetdm/src/ozmod/ozmod_wanpipe/ozmod_wanpipe.c
@@ -973,7 +973,12 @@ ZIO_SPAN_NEXT_EVENT_FUNCTION(wanpipe_next_event)
 					event_id = ZAP_OOB_NOOP;
 
 					//zap_log(ZAP_LOG_DEBUG, "%d:%d queue hardware dtmf %s\n", zchan->span_id, zchan->chan_id, tmp_dtmf);
+                    if (tdm_api.wp_tdm_cmd.event.wp_tdm_api_event_dtmf_type == WAN_EC_TONE_PRESENT) {
+						zap_set_flag_locked(zchan, ZAP_CHANNEL_MUTE);
+					}
+
                     if (tdm_api.wp_tdm_cmd.event.wp_tdm_api_event_dtmf_type == WAN_EC_TONE_STOP) {
+						zap_clear_flag_locked(zchan, ZAP_CHANNEL_MUTE);
                         zap_channel_queue_dtmf(zchan, tmp_dtmf);
                     } 
                 }