diff --git a/radio.c b/radio.c
index a818318..d0723b0 100644
--- a/radio.c
+++ b/radio.c
@@ -63,20 +63,6 @@ static radio_device_t *device;          // Device-dependent interface
 unsigned char radio_mem [1024*1024*2];  // Radio memory contents, up to 2 Mbytes
 int radio_progress;                     // Read/write progress counter
 
-//
-// Close the serial port.
-//
-void radio_disconnect()
-{
-    fprintf(stderr, "Close device.\n");
-
-    // Restore the normal radio mode.
-    dfu_reboot();
-    dfu_close();
-    hid_close();
-    serial_close();
-}
-
 //
 // Print a generic information about the device.
 //
diff --git a/src/radio.rs b/src/radio.rs
index d832b98..d49bdc0 100644
--- a/src/radio.rs
+++ b/src/radio.rs
@@ -7,7 +7,7 @@ pub struct RadioDeviceT { _private: [u8; 0] }
 
 extern {
   fn radio_connect() -> *const RadioDeviceT;
-  fn radio_disconnect();
+
   fn radio_download(device: *const RadioDeviceT);
   fn radio_upload(device: *const RadioDeviceT, cont_flag: c_int);
   fn radio_list_c();
@@ -18,6 +18,11 @@ extern {
   fn radio_save_image(device: *const RadioDeviceT, filename: *const c_char);
   fn radio_parse_config(device: *const RadioDeviceT, filename: *const c_char);
   fn radio_write_csv(device: *const RadioDeviceT, filename: *const c_char);
+
+  fn dfu_reboot();
+  fn dfu_close();
+  fn hid_close();
+  fn serial_close();
 }
 
 /// Connect to the radio via the serial port.
@@ -30,8 +35,14 @@ pub fn connect() -> *const RadioDeviceT {
 
 /// Close the serial port.
 pub fn disconnect() {
+
+  eprintln!("Close device.");
   unsafe {
-    radio_disconnect()
+    // Restore the normal radio mode.
+    dfu_reboot();
+    dfu_close();
+    hid_close();
+    serial_close();
   }
 }