diff --git a/audio/voice.h b/audio/voice.h
new file mode 100644
index 0000000..40bd1b1
--- /dev/null
+++ b/audio/voice.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2017 Christopher N. Hesse <raymanfx@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef VOICE_CALL_H
+#define VOICE_CALL_H
+
+#include "ril_interface.h"
+
+struct voice_session {
+    struct ril_handle ril;
+
+    struct pcm *pcm_voice_rx;
+    struct pcm *pcm_voice_tx;
+
+    bool wb_amr;
+    bool two_mic_control;
+    bool two_mic_disabled;
+
+    /* from uc_info */
+    audio_devices_t out_device;
+};
+
+struct voice_session *voice_session_init(void);
+void voice_session_deinit(struct voice_session *s);
+
+#endif /* VOICE_CALL_H */