diff --git a/src/hci.c b/src/hci.c
index 7022e682f..b72d15a34 100644
--- a/src/hci.c
+++ b/src/hci.c
@@ -954,8 +954,11 @@ static void hci_shutdown_connection(hci_connection_t *conn){
     log_info("Connection closed: handle 0x%x, %s", conn->con_handle, bd_addr_to_str(conn->address));
 
 #ifdef ENABLE_CLASSIC
-#ifdef ENABLE_SCO_OVER_HCI
-    int addr_type = conn->address_type;
+#if defined(ENABLE_SCO_OVER_HCI) || defined(HAVE_SCO_TRANSPORT)
+    bd_addr_type_t addr_type = conn->address_type;
+#endif
+#ifdef HAVE_SCO_TRANSPORT
+    hci_con_handle_t con_handle = conn->con_handle;
 #endif
 #endif
 
@@ -970,10 +973,15 @@ static void hci_shutdown_connection(hci_connection_t *conn){
 #ifdef ENABLE_CLASSIC
 #ifdef ENABLE_SCO_OVER_HCI
     // update SCO
-    if (addr_type == BD_ADDR_TYPE_SCO && hci_stack->hci_transport && hci_stack->hci_transport->set_sco_config){
+    if ((addr_type == BD_ADDR_TYPE_SCO) && (hci_stack->hci_transport != NULL) && (hci_stack->hci_transport->set_sco_config != NULL)){
         hci_stack->hci_transport->set_sco_config(hci_stack->sco_voice_setting_active, hci_number_sco_connections());
     }
 #endif
+#ifdef HAVE_SCO_TRANSPORT
+    if ((addr_type == BD_ADDR_TYPE_SCO) && (hci_stack->sco_transport != NULL)){
+        hci_stack->sco_transport->close(con_handle);
+    }
+#endif
 #endif
 }
 
@@ -2504,6 +2512,13 @@ static void event_handler(uint8_t *packet, uint16_t size){
             if (hci_have_usb_transport()){
                 hci_stack->sco_can_send_now = 1;
             }
+#endif
+#ifdef HAVE_SCO_TRANSPORT
+            // configure sco transport
+            if (hci_stack->sco_transport != NULL){
+                sco_format_t sco_format = ((hci_stack->sco_voice_setting_active & 0x03) == 0x03) ? SCO_FORMAT_8_BIT : SCO_FORMAT_16_BIT;
+                hci_stack->sco_transport->open(conn->con_handle, sco_format);
+            }
 #endif
             break;
 
@@ -3249,6 +3264,13 @@ void hci_close(void){
     hci_stack = NULL;
 }
 
+#ifdef HAVE_SCO_TRANSPORT
+void hci_set_sco_transport(const btstack_sco_transport_t *sco_transport){
+    hci_stack->sco_transport = sco_transport;
+    sco_transport->register_packet_handler(&packet_handler);
+}
+#endif
+
 #ifdef ENABLE_CLASSIC
 void gap_set_required_encryption_key_size(uint8_t encryption_key_size){
     // validate ranage and set
diff --git a/src/hci.h b/src/hci.h
index d18e072d1..3bffa866f 100644
--- a/src/hci.h
+++ b/src/hci.h
@@ -61,6 +61,10 @@
 #include "ble/att_db.h"
 #endif
 
+#ifdef HAVE_SCO_TRANSPORT
+#include "btstack_sco_transport.h"
+#endif
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -1000,6 +1004,10 @@ typedef struct {
 #ifdef ENABLE_CLASSIC_PAIRING_OOB
 	bool                      classic_read_local_oob_data;
 #endif
+
+#ifdef HAVE_SCO_TRANSPORT
+	const btstack_sco_transport_t * sco_transport;
+#endif
 } hci_stack_t;
 
 
@@ -1021,9 +1029,16 @@ void hci_set_chipset(const btstack_chipset_t *chipset_driver);
 
 /**
  * @brief Configure Bluetooth hardware control. Has to be called before power on.
+ * @[aram hardware_control implementation
  */
 void hci_set_control(const btstack_control_t *hardware_control);
 
+/**
+ * @brief Set SCO Transport implementation for SCO over PCM mode
+ * @param sco_transport that sends SCO over I2S or PCM interface
+ */
+void hci_set_sco_transport(const btstack_sco_transport_t *sco_transport);
+
 /**
  * @brief Configure Bluetooth hardware control. Has to be called before power on.
  */
@@ -1039,7 +1054,7 @@ void hci_set_hardware_error_callback(void (*fn)(uint8_t error));
  */
 void hci_set_bd_addr(bd_addr_t addr);
 
-/** 
+/**
  * @brief Configure Voice Setting for use with SCO data in HSP/HFP
  */
 void hci_set_sco_voice_setting(uint16_t voice_setting);