diff --git a/main.c b/main.c
index 50bbf17..0aa5f2b 100644
--- a/main.c
+++ b/main.c
@@ -49,128 +49,3 @@ void usage() {
 int main(int argc, char **argv) {
   return rust_main(argc, argv);
 }
-
-int old_c_main(int argc, char **argv)
-{
-    int read_flag = 0, write_flag = 0, config_flag = 0, csv_flag = 0;
-    int list_flag = 0, verify_flag = 0;
-
-    trace_flag = 0;
-    for (;;) {
-        switch (getopt(argc, argv, "tcwrulv")) {
-        case 't': ++trace_flag;  continue;
-        case 'r': ++read_flag;   continue;
-        case 'w': ++write_flag;  continue;
-        case 'c': ++config_flag; continue;
-        case 'u': ++csv_flag;    continue;
-        case 'l': ++list_flag;   continue;
-        case 'v': ++verify_flag; continue;
-        default:
-            usage();
-        case EOF:
-            break;
-        }
-        break;
-    }
-    argc -= optind;
-    argv += optind;
-    /*
-    if (list_flag) {
-        radio_list();
-        exit(0);
-    }
-    if (read_flag + write_flag + config_flag + csv_flag + verify_flag > 1) {
-        fprintf(stderr, "Only one of -r, -w, -c, -v or -u options is allowed.\n");
-        usage();
-    }
-    */
-    setvbuf(stdout, 0, _IOLBF, 0);
-    setvbuf(stderr, 0, _IOLBF, 0);
-
-    /*
-    if (write_flag) {
-        // Restore image file to device.
-        if (argc != 1)
-            usage();
-
-        radio_connect();
-        radio_read_image(argv[0]);
-        radio_print_version(stdout);
-        radio_upload(0);
-        radio_disconnect();
-
-    } else */if (config_flag) {
-        if (argc != 1 && argc != 2)
-            usage();
-
-        if (argc == 2) {
-            // Apply text config to image file.
-            radio_read_image(argv[0]);
-            radio_print_version(stdout);
-            radio_parse_config(argv[1]);
-            radio_verify_config();
-            radio_save_image("device.img");
-
-        } else {
-            // Update device from text config file.
-            radio_connect();
-            radio_download();
-            radio_print_version(stdout);
-            radio_save_image("backup.img");
-            radio_parse_config(argv[0]);
-            radio_verify_config();
-            radio_upload(1);
-            radio_disconnect();
-        }
-
-    } else if (verify_flag) {
-        if (argc != 1)
-	    usage();
-
-	// Verify text config file.
-	radio_connect();
-	radio_parse_config(argv[0]);
-	radio_verify_config();
-	radio_disconnect();
-
-    } else if (read_flag) {
-        if (argc != 0)
-            usage();
-
-        // Dump device to image file.
-        radio_connect();
-        radio_download();
-        radio_print_version(stdout);
-        radio_disconnect();
-        radio_save_image("device.img");
-
-        // Print configuration to file.
-        const char *filename = "device.conf";
-        printf("Print configuration to file '%s'.\n", filename);
-        FILE *conf = fopen(filename, "w");
-        if (!conf) {
-            perror(filename);
-            exit(-1);
-        }
-        radio_print_config(conf, 1);
-        fclose(conf);
-
-    } else if (csv_flag) {
-        // Update contacts database on the device.
-        if (argc != 1)
-            usage();
-
-        radio_connect();
-        radio_write_csv(argv[0]);
-        radio_disconnect();
-
-    } else {
-        if (argc != 1)
-            usage();
-
-        // Print configuration from image file.
-        radio_read_image(argv[0]);
-        radio_print_config(stdout, !isatty(1));
-    }
-    return 0;
-}
diff --git a/src/lib.rs b/src/lib.rs
index f341843..276df8f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,3 @@
-use std::ffi::CString;
 use libc::{c_int, c_char};
 use getopts::Options;
 use std::process::exit;
@@ -9,12 +8,11 @@ const COPYRIGHT: &'static str = "Copyright (C) 2018 Serge Vakulenko KK6ABQ";
 const VERSION: Option<&'static str> = option_env!("VERSION");
 
 extern {
-  fn old_c_main(argc: c_int, argv: *const *const c_char) -> c_int;
   fn radio_connect();
-  fn radio_read_image(filename: *const c_char);
-  fn radio_print_version(stdout: *const libc::FILE);
   fn radio_upload(cont_flag: c_int);
   fn radio_disconnect();
+  fn radio_verify_config();
+  fn radio_download();
 }
 
 #[no_mangle]
@@ -100,18 +98,94 @@ pub extern "C" fn rust_main(argc: c_int, argv: *const *const c_char) -> c_int {
     }
     unsafe {
       radio_connect();
-      let filename = CString::new(matches.free[0].clone()).unwrap();
-      radio_read_image(filename.as_ptr());
-      let mode = CString::new("w").unwrap();
-      radio_print_version(libc::fdopen(libc::STDOUT_FILENO, mode.as_ptr()));
+      radio::read_image(&matches.free[0]);
+      radio::print_version();
       radio_upload(0);
       radio_disconnect();
     }
+  } else if config_flag {
+    let conf_args = matches.free.len();
+    if !(conf_args == 1 || conf_args == 2) {
+      print_usage();
+    }
+    let (config_filename, image_filename) = if conf_args == 2 {
+      (matches.free[1].clone(), Some(matches.free[0].clone()))
+    } else {
+      (matches.free[0].clone(), None)
+    };
+
+    if let Some(img) = image_filename {
+      // Apply text config to image file.
+      unsafe { 
+        radio::read_image(&img);
+        radio::print_version();
+        radio::parse_config(&config_filename);
+        radio_verify_config();
+        radio::save_image("device.img");
+      }
+    } else {
+      // Update device from text config file.
+      unsafe {
+        radio_connect();
+        radio_download();
+        radio::print_version();
+        radio::save_image("device.img");
+        radio::parse_config(&config_filename);
+        radio_verify_config();
+        radio_upload(1);
+        radio_disconnect();
+      }
+    }
+  } else if verify_flag {
+    if matches.free.len() != 1 {
+      print_usage();
+    }
+    // Verify text config file.
+    unsafe {
+      radio_connect();
+      radio::parse_config(&matches.free[0]);
+      radio_verify_config();
+      radio_disconnect();
+    }
+  } else if read_flag {
+    if matches.free.len() != 0 {
+      print_usage();
+    }
+
+    // Dump device to image file.
+    unsafe {
+      radio_connect();
+      radio_download();
+      radio::print_version();
+      radio_disconnect();
+      radio::save_image("device.img");
+    }
+
+    // Print configuration to file.
+    let filename = "device.conf";
+    println!("Print configuration to file '{}.", filename);
+
+    radio::print_config(filename);
+
+  } else if csv_flag {
+    if matches.free.len() != 1 {
+      print_usage();
+    }
+
+    unsafe {
+    radio_connect();
+    radio::write_csv(&matches.free[0]);
+    radio_disconnect();
+    }
+  } else {
+    if matches.free.len() != 1 {
+      print_usage();
+    }
+    radio::read_image(&matches.free[0]);
+    radio::print_config_to_stdout();
   }
 
-  unsafe {
-    old_c_main(argc, argv)
-  }
+  exit(0);
 }
 
 #[cfg(test)]
diff --git a/src/radio.rs b/src/radio.rs
index fc9bdde..548d524 100644
--- a/src/radio.rs
+++ b/src/radio.rs
@@ -1,5 +1,15 @@
+use std::ffi::CString;
+use libc::{c_char, c_int};
+use std::os::unix::io::AsRawFd;
+
 extern {
   fn radio_list_c();
+  fn radio_print_version(stdout: *const libc::FILE);
+  fn radio_print_config(file: *const libc::FILE, verbose: c_int);
+  fn radio_read_image(filename: *const c_char);
+  fn radio_save_image(filename: *const c_char);
+  fn radio_parse_config(filename: *const c_char);
+  fn radio_write_csv(filename: *const c_char);
 }
 
 pub fn list() {
@@ -7,3 +17,62 @@ pub fn list() {
     radio_list_c();
   }
 }
+
+pub fn read_image(filename: &str) {
+  let filename = CString::new(filename.to_string()).unwrap();
+  unsafe {
+    radio_read_image(filename.as_ptr());
+  }
+}
+
+pub fn save_image(filename: &str) {
+  let filename = CString::new(filename.to_string()).unwrap();
+  unsafe {
+    radio_save_image(filename.as_ptr())
+  }
+}
+
+pub fn parse_config(filename: &str) {
+  let filename = CString::new(filename.to_string()).unwrap();
+  unsafe {
+    radio_parse_config(filename.as_ptr())
+  }
+}
+
+pub fn print_config(filename: &str) {
+  let file = std::fs::File::create(filename).unwrap();
+  let fd = file.as_raw_fd();
+  let mode = CString::new("w").unwrap();
+  unsafe {
+    let file =libc::fdopen(fd, mode.as_ptr());
+    radio_print_config(file, 1);
+    libc::fclose(file);
+  }
+}
+
+pub fn print_config_to_stdout() {
+  let mode = CString::new("w").unwrap();
+  unsafe {
+    let stdout = libc::fdopen(libc::STDOUT_FILENO, mode.as_ptr());
+    let verbosity = if libc::isatty(libc::STDOUT_FILENO) == 1 {
+      0
+    } else {
+      1
+    };
+    radio_print_config(stdout, verbosity);
+  }
+}
+
+pub fn print_version() {
+  let mode = CString::new("w").unwrap();
+  unsafe {
+    radio_print_version(libc::fdopen(libc::STDOUT_FILENO, mode.as_ptr()));
+  }
+}
+
+pub fn write_csv(filename: &str) {
+  let filename = CString::new(filename.to_string()).unwrap();
+  unsafe {
+    radio_write_csv(filename.as_ptr());
+  }
+}