diff --git a/src/main.rs b/src/main.rs
index 8590849..bd1a330 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -204,15 +204,22 @@ pub mod uart_transact {
             filename = format!("../log/commands_{}.log", Perf::cur_time("%Y%m%d")); 
             let cmd_writer = Logger::new(filename.clone(), save_data_flag)?; 
 
-            let port = serialport::new(port_name, port_settings.baud_rate)
-                .timeout(Duration::from_millis(port_settings.timeout_msec)).open().unwrap();
+            let mut port = Self::set_port_settings(port_name, 
+                                                   port_settings.clone()).unwrap();
 
             let tx_packet = String::new();
             let rx_packet = String::new();
 
-            Ok( Self { type_, port_name: port_name.to_string(), port_settings, save_data_flag, save_cmd_flag, 
-                data_writer, cmd_writer,
-                port, tx_packet, rx_packet,
+            Ok( Self { type_, 
+                port_name: port_name.to_string(), 
+                port_settings, 
+                save_data_flag, 
+                save_cmd_flag, 
+                data_writer, 
+                cmd_writer,
+                port, 
+                tx_packet, 
+                rx_packet,
             })
         }
 
@@ -231,13 +238,13 @@ pub mod uart_transact {
             if self.type_ == TypeEn::TxRx  {
                 self.cmd_writer.log(&self.tx_packet).unwrap();
 
-                // self.tx_packet.push_str(std::str::from_utf8(b"\x0D\x0A").unwrap()); // CR + LF
-                println!("write to port: ({:?})", self.tx_packet.as_bytes());
-                match self.port.write_all(&self.tx_packet.as_bytes()) {
+                match self.port.write(&self.tx_packet.as_bytes()) {
                     Ok(_) => {},
                     Err(e) => eprintln!("Error sending data: {}", e),
                 }
 
+                self.port.flush().unwrap();
+
                 // let mut buffer = [0u8; 4096];
                 // self.port.read(&mut buffer);
                 // let s = std::str::from_utf8(&buffer).unwrap().to_string();