diff --git a/example/embedded/hsp_hs_test.c b/example/embedded/hsp_hs_test.c
index 1cf61bb22..b8f372978 100644
--- a/example/embedded/hsp_hs_test.c
+++ b/example/embedded/hsp_hs_test.c
@@ -239,7 +239,7 @@ int btstack_main(int argc, const char * argv[]){
     
     sdp_init();
 	memset((uint8_t *)hsp_service_buffer, 0, sizeof(hsp_service_buffer));
-    hsp_hs_create_service((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_hs_service_name, 0);
+    hsp_hs_create_sdp_record((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_hs_service_name, 0);
 
     sdp_register_service_internal(NULL, (uint8_t *)hsp_service_buffer);
 
diff --git a/src/hfp_ag.c b/src/hfp_ag.c
index 5c16a6320..a5f4c84a5 100644
--- a/src/hfp_ag.c
+++ b/src/hfp_ag.c
@@ -37,7 +37,7 @@
  
 // *****************************************************************************
 //
-// Minimal setup for HFP Audio Gateway (AG) unit (!! UNDER DEVELOPMENT !!)
+// HFP Audio Gateway (AG) unit
 //
 // *****************************************************************************
 
@@ -51,16 +51,16 @@
 #include <btstack/hci_cmds.h>
 #include <btstack/run_loop.h>
 
-#include "hci.h"
 #include "btstack_memory.h"
-#include "hci_dump.h"
-#include "l2cap.h"
-#include "sdp_query_rfcomm.h"
-#include "sdp.h"
 #include "debug.h"
+#include "hci.h"
+#include "hci_dump.h"
 #include "hfp.h"
-#include "hfp_gsm_model.h"
 #include "hfp_ag.h"
+#include "hfp_gsm_model.h"
+#include "l2cap.h"
+#include "sdp.h"
+#include "sdp_query_rfcomm.h"
 
 static const char default_hfp_ag_service_name[] = "Voice gateway";
 
diff --git a/src/hfp_ag.h b/src/hfp_ag.h
index 6df0ba6cd..b14982de9 100644
--- a/src/hfp_ag.h
+++ b/src/hfp_ag.h
@@ -37,7 +37,7 @@
 
 // *****************************************************************************
 //
-//  Minimal setup for HFP Audio Gateway (AG) unit (!! UNDER DEVELOPMENT !!)
+// HFP Audio Gateway (AG) unit
 //
 // *****************************************************************************
 
@@ -46,9 +46,7 @@
 #define btstack_hfp_ag_h
 
 #include "hci.h"
-#include "sdp_query_rfcomm.h"
 #include "hfp.h"
-#include "hfp_gsm_model.h"
 
 #if defined __cplusplus
 extern "C" {
@@ -80,6 +78,14 @@ void hfp_ag_init(uint16_t rfcomm_channel_nr, uint32_t supported_features,
  */
 void hfp_ag_register_packet_handler(hfp_callback_t callback);
 
+/**
+ * @brief Enable in-band ring tone
+ */
+void hfp_ag_set_use_in_band_ring_tone(int use_in_band_ring_tone);
+
+
+// actions used by local device / user
+
 /**
  * @brief Establish RFCOMM connection, and perform service level connection agreement:
  * - exchange of supported features
@@ -93,72 +99,10 @@ void hfp_ag_establish_service_level_connection(bd_addr_t bd_addr);
 
 /**
  * @brief Release the RFCOMM channel and the audio connection between the HF and the AG. 
- * TODO: trigger release of the audio connection
+ * TODO: trigger release of the audio connection ??
  */
 void hfp_ag_release_service_level_connection(bd_addr_t bd_addr);
 
-/**
- * @brief Report Extended Audio Gateway Error result codes in the AG.
- * Whenever there is an error relating to the functionality of the AG as a 
- * result of AT command, the AG shall send +CME ERROR:
- * - +CME ERROR: 0  - AG failure
- * - +CME ERROR: 1  - no connection to phone 
- * - +CME ERROR: 3  - operation not allowed 
- * - +CME ERROR: 4  - operation not supported 
- * - +CME ERROR: 5  - PH-SIM PIN required 
- * - +CME ERROR: 10 - SIM not inserted 
- * - +CME ERROR: 11 - SIM PIN required 
- * - +CME ERROR: 12 - SIM PUK required 
- * - +CME ERROR: 13 - SIM failure
- * - +CME ERROR: 14 - SIM busy
- * - +CME ERROR: 16 - incorrect password 
- * - +CME ERROR: 17 - SIM PIN2 required 
- * - +CME ERROR: 18 - SIM PUK2 required 
- * - +CME ERROR: 20 - memory full
- * - +CME ERROR: 21 - invalid index
- * - +CME ERROR: 23 - memory failure
- * - +CME ERROR: 24 - text string too long
- * - +CME ERROR: 25 - invalid characters in text string
- * - +CME ERROR: 26 - dial string too long
- * - +CME ERROR: 27 - invalid characters in dial string
- * - +CME ERROR: 30 - no network service
- * - +CME ERROR: 31 - network Timeout.
- * - +CME ERROR: 32 - network not allowed – Emergency calls only
- */
-void hfp_ag_report_extended_audio_gateway_error_result_code(bd_addr_t bd_addr, hfp_cme_error_t error);
-
-/**
- * @brief Report the change in AG's call status. 
- * Call status:
- * - 0 = No calls (held or active)
- * - 1 = Call is present (active or held) 
- */
-void hfp_ag_transfer_call_status(bd_addr_t bd_addr, hfp_call_status_t status);
-
-/**
- * @brief Report the change in AG's call setup status.
- * Call setup status:
- * - 0 = No call setup in progress 
- * - 1 = Incoming call setup in progress
- * - 2 = Outgoing call setup in dialing state
- * - 3 = Outgoing call setup in alerting state
- */
-void hfp_ag_transfer_callsetup_status(bd_addr_t bd_addr, hfp_callsetup_status_t status);
-
-/**
- * @brief Report the change in AG's held call status.
- * Held call status:
- * - 0 = No calls held
- * - 1 = Call is placed on hold or active/held calls are swapped
- * - 2 = Call on hold, no active calls
- */
-void hfp_ag_transfer_callheld_status(bd_addr_t bd_addr, hfp_callheld_status_t status);
-
-/**
- * @brief 
- */
-void hfp_ag_negotiate_codecs(bd_addr_t bd_addr);
-
 /**
  * @brief 
  */
@@ -169,11 +113,76 @@ void hfp_ag_establish_audio_connection(bd_addr_t bd_addr);
  */
 void hfp_ag_release_audio_connection(bd_addr_t bd_addr);
 
+/**
+ * @brief 
+ */
+void hfp_ag_answer_incoming_call(void);
 
 /**
- * @brief Enable in-band ring tone
+ * @brief 
  */
-void hfp_ag_set_use_in_band_ring_tone(int use_in_band_ring_tone);
+void hfp_ag_join_held_call(void);
+
+/**
+ * @brief 
+ */
+void hfp_ag_terminate_call(void);
+
+/*
+ * @brief
+ */
+void hfp_ag_hold_incoming_call(void);
+
+/*
+ * @brief
+ */
+void hfp_ag_accept_held_incoming_call(void);
+
+/*
+ * @brief
+ */
+void hfp_ag_reject_held_incoming_call(void);
+
+/*
+ * @brief
+ */
+void hfp_ag_set_microphone_gain(bd_addr_t bd_addr, int gain);
+
+/*
+ * @brief
+ */
+void hfp_ag_set_speaker_gain(bd_addr_t bd_addr, int gain);
+
+/*
+ * @brief
+ */
+void hfp_ag_set_battery_level(int level);
+
+/*
+ * @brief
+ */
+void hfp_ag_clear_last_dialed_number(void);
+
+
+// Voice Recognition
+
+/*
+ * @brief
+ */
+void hfp_ag_activate_voice_recognition(bd_addr_t bd_addr, int activate);
+
+/*
+ * @brief
+ */
+void hfp_ag_send_phone_number_for_voice_tag(bd_addr_t bd_addr, const char * number);
+
+/*
+ * @brief
+ */
+void hfp_ag_reject_phone_number_for_voice_tag(bd_addr_t bd_addr);
+
+
+// Cellular Actions
 
 /**
  * @brief 
@@ -209,22 +218,6 @@ void hfp_ag_outgoing_call_established(void);
  * @brief 
  */
 void hfp_ag_call_dropped(void);
-
-/**
- * @brief 
- */
-void hfp_ag_answer_incoming_call(void);
-
-/**
- * @brief 
- */
-void hfp_ag_join_held_call(void);
-
-/**
- * @brief 
- */
-void hfp_ag_terminate_call(void);
-
 /*
  * @brief
  */
@@ -240,75 +233,49 @@ void hfp_ag_set_signal_strength(int strength);
  */
 void hfp_ag_set_roaming_status(int status);
 
-/*
- * @brief
- */
-void hfp_ag_set_battery_level(int level);
-
-
-/*
- * @brief
- */
-void hfp_ag_activate_voice_recognition(bd_addr_t bd_addr, int activate);
-
-/*
- * @brief
- */
-void hfp_ag_set_microphone_gain(bd_addr_t bd_addr, int gain);
-
-/*
- * @brief
- */
-void hfp_ag_set_speaker_gain(bd_addr_t bd_addr, int gain);
-
-/*
- * @brief
- */
-void hfp_ag_send_phone_number_for_voice_tag(bd_addr_t bd_addr, const char * number);
-
-/*
- * @brief
- */
-void hfp_ag_reject_phone_number_for_voice_tag(bd_addr_t bd_addr);
-
-/*
- * @brief
- */
-void hfp_ag_send_dtmf_code_done(bd_addr_t bd_addr);
-
 /*
  * @brief
  */
 void hfp_ag_set_subcriber_number_information(hfp_phone_number_t * numbers, int numbers_count);
 
 /*
- * @brief
+ * @brief Called by cellular unit after a DTMF code was transmitted, so that the next one can be emitted
  */
+void hfp_ag_send_dtmf_code_done(bd_addr_t bd_addr);
 
-void hfp_ag_send_current_call_status(bd_addr_t bd_addr, int idx);
-
-/*
- * @brief
+/**
+ * @brief Report Extended Audio Gateway Error result codes in the AG.
+ * Whenever there is an error relating to the functionality of the AG as a 
+ * result of AT command, the AG shall send +CME ERROR:
+ * - +CME ERROR: 0  - AG failure
+ * - +CME ERROR: 1  - no connection to phone 
+ * - +CME ERROR: 3  - operation not allowed 
+ * - +CME ERROR: 4  - operation not supported 
+ * - +CME ERROR: 5  - PH-SIM PIN required 
+ * - +CME ERROR: 10 - SIM not inserted 
+ * - +CME ERROR: 11 - SIM PIN required 
+ * - +CME ERROR: 12 - SIM PUK required 
+ * - +CME ERROR: 13 - SIM failure
+ * - +CME ERROR: 14 - SIM busy
+ * - +CME ERROR: 16 - incorrect password 
+ * - +CME ERROR: 17 - SIM PIN2 required 
+ * - +CME ERROR: 18 - SIM PUK2 required 
+ * - +CME ERROR: 20 - memory full
+ * - +CME ERROR: 21 - invalid index
+ * - +CME ERROR: 23 - memory failure
+ * - +CME ERROR: 24 - text string too long
+ * - +CME ERROR: 25 - invalid characters in text string
+ * - +CME ERROR: 26 - dial string too long
+ * - +CME ERROR: 27 - invalid characters in dial string
+ * - +CME ERROR: 30 - no network service
+ * - +CME ERROR: 31 - network Timeout.
+ * - +CME ERROR: 32 - network not allowed – Emergency calls only
  */
-void hfp_ag_hold_incoming_call(void);
-
-/*
- * @brief
- */
-void hfp_ag_accept_held_incoming_call(void);
-
-/*
- * @brief
- */
-void hfp_ag_reject_held_incoming_call(void);
-
-/*
- * @brief
- */
-void hfp_ag_clear_last_dialed_number(void);
+void hfp_ag_report_extended_audio_gateway_error_result_code(bd_addr_t bd_addr, hfp_cme_error_t error);
 
 /* API_END */
 
+
 #if defined __cplusplus
 }
 #endif
diff --git a/src/hfp_hf.h b/src/hfp_hf.h
index 5e764e50f..a9393c06d 100644
--- a/src/hfp_hf.h
+++ b/src/hfp_hf.h
@@ -37,13 +37,13 @@
 
 // *****************************************************************************
 //
-//  Minimal setup for HFP Hands-Free (HF) unit (!! UNDER DEVELOPMENT !!)
+//  HFP Hands-Free (HF) unit
 //
 // *****************************************************************************
 
 
-#ifndef btstack_hfp_hf_h
-#define btstack_hfp_hf_h
+#ifndef __BTSTACK_HFP_HF_H
+#define __BTSTACK_HFP_HF_H
 
 #include "hci.h"
 #include "sdp_query_rfcomm.h"
@@ -55,7 +55,6 @@ extern "C" {
 
 /* API_START */
 
-
 /**
  * @brief Create HFP Hands-Free (HF) SDP service record. 
  */
@@ -66,8 +65,11 @@ void hfp_hf_create_sdp_record(uint8_t * service, int rfcomm_channel_nr, const ch
  * TODO:  move optional params into setters
  */
 void hfp_hf_init(uint16_t rfcomm_channel_nr, uint32_t supported_features, uint16_t * indicators, int indicators_nr, uint32_t indicators_status);
+
 void hfp_hf_set_codecs(uint8_t * codecs, int codecs_nr);
 
+void hfp_hf_set_supported_features(uint32_t supported_features);
+
 /**
  * @brief Register callback for the HFP Hands-Free (HF) client. 
  */
@@ -83,7 +85,6 @@ void hfp_hf_register_packet_handler(hfp_callback_t callback);
  * - retrieve which HF indicators are enabled on the AG, if possible
  */
 void hfp_hf_establish_service_level_connection(bd_addr_t bd_addr);
-void hfp_hf_set_supported_features(uint32_t supported_features);
 
 /**
  * @brief Release the RFCOMM channel and the audio connection between the HF and the AG. 
@@ -95,6 +96,7 @@ void hfp_hf_release_service_level_connection(bd_addr_t bd_addr);
  * @brief Deactivate/reactivate status update for all indicators in the AG.
  */
 void hfp_hf_enable_status_update_for_all_ag_indicators(bd_addr_t bd_addr);
+
 void hfp_hf_disable_status_update_for_all_ag_indicators(bd_addr_t bd_addr);
 
 /**
@@ -106,6 +108,8 @@ void hfp_hf_set_status_update_for_individual_ag_indicators(bd_addr_t bd_addr, ui
 /**
  * @brief Find out the name of the currently selected Network operator by AG. 
  * The name is restricted to max 16 characters.
+ *
+ * TODO: what is the result of this?
  */
 void hfp_hf_query_operator_selection(bd_addr_t bd_addr);
 
@@ -196,7 +200,8 @@ void hfp_hf_terminate_call(bd_addr_t bd_addr);
 void hfp_hf_dial_number(bd_addr_t bd_addr, char * number);
 
 /**
- * @brief 
+ * @brief
+ * TODO: use int for number instead of string? 
  */
 void hfp_hf_dial_memory(bd_addr_t bd_addr, char * number);
 
@@ -317,4 +322,4 @@ void hfp_hf_set_hf_indicator(bd_addr_t addr, int assigned_number, int value);
 }
 #endif
 
-#endif
\ No newline at end of file
+#endif // __BTSTACK_HFP_HF_H
\ No newline at end of file
diff --git a/src/hsp_ag.c b/src/hsp_ag.c
index fbe24d502..128c13eaf 100644
--- a/src/hsp_ag.c
+++ b/src/hsp_ag.c
@@ -146,7 +146,7 @@ static void emit_event_audio_connected(uint8_t status, uint16_t handle){
     (*hsp_hs_callback)(event, sizeof(event));
 }
 
-void hsp_ag_create_service(uint8_t * service, int rfcomm_channel_nr, const char * name){
+void hsp_ag_create_sdp_record(uint8_t * service, int rfcomm_channel_nr, const char * name){
     uint8_t* attribute;
     de_create_sequence(service);
 
diff --git a/src/hsp_ag.h b/src/hsp_ag.h
index 7c9646021..9f72d68a9 100644
--- a/src/hsp_ag.h
+++ b/src/hsp_ag.h
@@ -54,9 +54,11 @@ extern "C" {
 
 typedef void (*hsp_ag_callback_t)(uint8_t * event, uint16_t event_size);
 
-void hsp_ag_init(uint8_t rfcomm_channel_nr);
 
-void hsp_ag_create_service(uint8_t * service, int rfcomm_channel_nr, const char * name);
+void hsp_ag_create_sdp_record(uint8_t * service, int rfcomm_channel_nr, const char * name);
+
+
+void hsp_ag_init(uint8_t rfcomm_channel_nr);
 
 // Register callback (packet handler) for hsp audio gateway
 void hsp_ag_register_packet_handler(hsp_ag_callback_t callback);
diff --git a/src/hsp_hs.c b/src/hsp_hs.c
index 778b62e48..f55cc27c6 100644
--- a/src/hsp_hs.c
+++ b/src/hsp_hs.c
@@ -165,7 +165,7 @@ int hsp_hs_send_result(char * result){
 }
 
 
-void hsp_hs_create_service(uint8_t * service, int rfcomm_channel_nr, const char * name, uint8_t have_remote_audio_control){
+void hsp_hs_create_sdp_record(uint8_t * service, int rfcomm_channel_nr, const char * name, uint8_t have_remote_audio_control){
     uint8_t* attribute;
     de_create_sequence(service);
 
diff --git a/src/hsp_hs.h b/src/hsp_hs.h
index 07e0085b7..4f54ac892 100644
--- a/src/hsp_hs.h
+++ b/src/hsp_hs.h
@@ -56,7 +56,7 @@ typedef void (*hsp_hs_callback_t)(uint8_t * event, uint16_t event_size);
 
 void hsp_hs_init(uint8_t rfcomm_channel_nr);
 
-void hsp_hs_create_service(uint8_t * service, int rfcomm_channel_nr, const char * name, uint8_t have_remote_audio_control);
+void hsp_hs_create_sdp_record(uint8_t * service, int rfcomm_channel_nr, const char * name, uint8_t have_remote_audio_control);
 
 // Register callback (packet handler) for hsp headset
 void hsp_hs_register_packet_handler(hsp_hs_callback_t callback);
diff --git a/test/pts/hsp_ag_test.c b/test/pts/hsp_ag_test.c
index b7964b015..d9ea3f03a 100644
--- a/test/pts/hsp_ag_test.c
+++ b/test/pts/hsp_ag_test.c
@@ -186,7 +186,7 @@ int btstack_main(int argc, const char * argv[]);
 int btstack_main(int argc, const char * argv[]){
     // init SDP, create record for SPP and register with SDP
     memset((uint8_t *)hsp_service_buffer, 0, sizeof(hsp_service_buffer));
-    hsp_ag_create_service((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_ag_service_name);
+    hsp_ag_create_sdp_record((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_ag_service_name);
     
     hsp_ag_init(rfcomm_channel_nr);
     hsp_ag_register_packet_handler(packet_handler);
diff --git a/test/pts/hsp_hs_test.c b/test/pts/hsp_hs_test.c
index a52de2809..d25f8d019 100644
--- a/test/pts/hsp_hs_test.c
+++ b/test/pts/hsp_hs_test.c
@@ -317,7 +317,7 @@ int btstack_main(int argc, const char * argv[]){
     hci_register_sco_packet_handler(&sco_packet_handler);
 
     memset((uint8_t *)hsp_service_buffer, 0, sizeof(hsp_service_buffer));
-    hsp_hs_create_service((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_hs_service_name, 0);
+    hsp_hs_create_sdp_record((uint8_t *)hsp_service_buffer, rfcomm_channel_nr, hsp_hs_service_name, 0);
 
     hsp_hs_init(rfcomm_channel_nr);
     hsp_hs_register_packet_handler(packet_handler);