diff --git a/src/main.rs b/src/main.rs
index 8a627ae..7852eb9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,6 +7,8 @@ use rustyline::Editor;
 use rustyline::error::ReadlineError;
 use std::fs::OpenOptions;
 use std::io::{BufReader, BufRead};
+use std::net::{TcpListener, TcpStream};
+use std::collections::HashMap;
 
 pub mod perf {
     use chrono::{DateTime, Duration, Utc, Local};
@@ -16,6 +18,7 @@ pub mod perf {
         end: DateTime<Utc>,
         delta_ms: i64,
         delta_mks: i64,
+        delta_ns: i64,
     }
 
     impl Perf  {
@@ -25,6 +28,7 @@ pub mod perf {
                 end: Utc::now(),
                 delta_ms: 0,
                 delta_mks: 0,
+                delta_ns: 0,
             }
         }
 
@@ -37,9 +41,11 @@ pub mod perf {
             self.end = Utc::now();
             self.delta_ms = (self.end - self.start).num_microseconds().unwrap()/1000;
             self.delta_mks = (self.end - self.start).num_microseconds().unwrap();
+            self.delta_ns = (self.end - self.start).num_nanoseconds().unwrap();
 
-            if (measure == "ms") { println!("{} (ms): {:?}", out_msg, self.delta_ms); }
-            else { println!("{} (mks): {:?}", out_msg, self.delta_mks); }
+            if (measure == "mks") { println!("{} (mks): {:?}", out_msg, self.delta_mks); }
+            else if (measure == "ns") { println!("{} (ns): {:?}", out_msg, self.delta_ns); }
+            else { println!("{} (ms): {:?}", out_msg, self.delta_ms); }
         }
 
         pub fn stop_restart(&mut self, out_msg: &str, measure: &str) {
@@ -56,6 +62,285 @@ pub mod perf {
     }
 }
 
+use crate::perf::Perf;
+
+fn tcp_server() {
+    let listener = TcpListener::bind("127.0.0.1:10000").unwrap();
+    println!("TCP-server is running");
+
+    for stream in listener.incoming() {
+        match stream {
+            Ok(stream) => {
+                println!("connect to client: {:?}", stream);
+                handle_client(stream);
+
+            },
+            Err(ref msg) => {
+                println!("error: failed attempt to set connection with client: ({:?}): {}", 
+                         stream, msg);
+            }
+        }
+    }
+}
+
+fn handle_client(mut stream: TcpStream) {
+    let mut cmd_descr: HashMap::<&str, &str> = HashMap::new();
+    cmd_descr.insert("send", "send data to serial port");
+    cmd_descr.insert("exit", "cancel connection with server");
+
+    loop {
+        let mut reader = BufReader::new(&stream);
+        let mut rx_data = String::new();
+        if let Err(msg) = reader.read_line(&mut rx_data) {
+            println!("error: failed attempt to read data from client: {}", msg);
+            return;
+        }
+
+        if rx_data.contains("exit") {
+            println!("The client requested to close the connection");
+            return;
+        }
+    }
+}
+
+
+pub mod uartTransact {
+    const MAX_BUF: usize = 4096;
+    use serialport::{SerialPort, StopBits, Parity, FlowControl, DataBits};
+    use std::time::Duration;
+    use crate::perf::Perf;
+    use std::io::{self, Read, Write, BufWriter, BufReader, BufRead};
+    use std::fs::{File, OpenOptions};
+    use std::path::Path;
+
+    #[derive(PartialEq)]
+    pub enum Type_en {
+        rx = 0,
+        tx,
+        rx_tx,
+        tx_rx,
+    }
+
+    #[derive(Clone)]
+    pub struct PortSettings_t {
+        baud_rate: u32,
+        data_bits: DataBits,
+        parity: Parity,
+        stop_bits: StopBits,
+        flow_ctrl: FlowControl,
+        timeout_msec: u64,
+    }
+
+    impl PortSettings_t {
+        pub fn new(baud_rate: u32, data_bits_: u8, parity_: &str, stop_bits_: u8,
+                   flow_ctrl_: &str, timeout_msec: u64) -> Result<Self, String> {
+
+            let data_bits = match data_bits_ {
+                5 => DataBits::Five,
+                6 => DataBits::Six,
+                7 => DataBits::Seven,
+                8 => DataBits::Eight,
+                _ => { return Err(format!(
+                            "error: the number of data bits specified is incorrect 
+                            (type from 5 to 8)")); 
+                }
+            };
+
+            let parity = match parity_ {
+                "Even" => Parity::Even,
+                "Odd" => Parity::Odd,
+                "None" => Parity::None,
+                _ => { return Err(format!(
+                            "error: the parity of data specified is incorrect 
+                            (type \"Even\", \"Odd\" or \"None\")")); 
+                }
+            };
+
+            let stop_bits = match stop_bits_ {
+                1 => StopBits::One,
+                2 => StopBits::Two,
+                _ => { return Err(format!(
+                            "error: the stop bits of data specified is incorrect 
+                            (type 1 or 2)")); 
+                }
+            };
+
+            let flow_ctrl = match flow_ctrl_ {
+                "None" => FlowControl::None,
+                "Software" => FlowControl::Software,
+                "Hardware" => FlowControl::Hardware,
+                _ => { return Err(format!(
+                            "error: the parity of data specified is incorrect 
+                            (type \"None\", \"Software\" or \"Hardware\")")); 
+                }
+            };
+
+            Ok(Self { baud_rate, data_bits, parity, stop_bits, flow_ctrl, timeout_msec })
+        }
+    }
+
+    struct Packet_t {
+        buf: [u8; MAX_BUF],
+        size: u32,
+    }
+
+    impl Packet_t {
+        pub fn new(buf: [u8; MAX_BUF], size: u32) -> Packet_t {
+            Packet_t { buf, size }
+        }
+    }
+
+    struct Logger {
+        out: BufWriter<File>, 
+        log_flag: bool,
+    }
+
+    impl Logger {
+        fn new<P: AsRef<Path>>(filename: P, log_flag: bool) -> Result<Self, io::Error> {
+            let path = Path::new(filename.as_ref());
+
+            let mut file = match path.exists() {
+                true => OpenOptions::new().write(true).append(true).open(filename.as_ref())?,
+                false => File::create(filename.as_ref())?
+            };
+
+            let out = BufWriter::new(file);
+
+            Ok(Self { out, log_flag })
+        }
+
+        fn log(&mut self, msg: &str) -> Result<(), io::Error> {
+            if self.log_flag == true {
+                writeln!(&mut self.out, "{} {};{:?}", 
+                         Perf::cur_time("%Y.%m.%d"), 
+                         Perf::cur_time("%H:%M:%S.%3f"),
+                         msg.trim())?;
+                self.out.flush()?;
+            }
+            Ok(())
+        }
+    }
+
+    pub struct UartTransact {
+        type_: Type_en,
+        port_name: String,
+        port_settings: PortSettings_t,
+        tx_packet: String,
+        rx_packet: String,
+
+        port: Box<dyn SerialPort>, 
+        save_data_flag: bool,
+        save_cmd_flag: bool,
+        data_writer: Logger,
+        cmd_writer: Logger,
+    }
+
+    impl UartTransact {
+        pub fn new(trans_type: &str, 
+                   port_name: &str, 
+                   port_settings: PortSettings_t,
+                   save_data_flag: bool,
+                   save_cmd_flag: bool) -> Result<Self, io::Error> {
+
+            let mut type_ = Type_en::tx_rx;
+            if trans_type == "tx_rx" { type_ = Type_en::tx_rx;  }
+            else if trans_type == "tx" { type_ = Type_en::rx;  }
+            else if trans_type == "rx_tx" { type_ = Type_en::rx_tx;  }
+            else if trans_type == "rx" { type_ = Type_en::rx;  }
+
+            let mut filename = format!("../log/data_{}.log", Perf::cur_time("%Y%m%d")); 
+            let data_writer = Logger::new(filename.clone(), save_data_flag)?; 
+            filename = format!("../log/commands_{}.log", Perf::cur_time("%Y%m%d")); 
+            let cmd_writer = Logger::new(filename.clone(), save_data_flag)?; 
+
+            let mut port = serialport::new(port_name.clone(), port_settings.baud_rate)
+                .timeout(Duration::from_millis(port_settings.timeout_msec)).open().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,
+            })
+        }
+
+
+        pub fn addPacketForTx(&mut self, buf: String, size: u32) -> Result<(), String> {
+            if size as usize >= MAX_BUF {
+                return Err(format!("too much data for transmit! Data size must be < {} bytes", MAX_BUF));
+            }
+            else { self.tx_packet = buf; }
+
+            return Ok(());
+        }
+
+        pub fn startTransact(&mut self) -> Result<(), String> {
+
+            if self.type_ == Type_en::tx_rx  {
+                self.cmd_writer.log(&self.tx_packet).unwrap();
+
+                match self.port.write(&self.tx_packet.as_bytes()) {
+                    Ok(_) => {},
+                    Err(e) => eprintln!("Error sending data: {}", e),
+                }
+
+                // self.port.flush().unwrap();
+
+                let mut reader = BufReader::new(&mut self.port);
+
+                let mut s = String::new();
+                if let Err(err) = reader.read_line(&mut s) {
+                    println!("error: {}", err);
+                    return Ok(());
+                }
+                if s.len() > 0 {
+                    self.rx_packet = s.clone();
+                    self.data_writer.log(&s).unwrap();
+                }
+            }
+            Ok(())
+        }
+
+        pub fn getReceivedPacket(&mut self) -> String {
+            self.rx_packet.clone()
+        }
+
+        fn set_port_settings(port_name: &str, 
+                             set: PortSettings_t) -> Result<Box<dyn SerialPort>, String> {
+
+            let mut port = match serialport::new(port_name, set.baud_rate)
+                .timeout(Duration::from_millis(set.timeout_msec)).open() {
+                    Ok(p) => p,
+                    Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+                };
+
+            match port.set_baud_rate(set.baud_rate) {
+                Ok(_) => {},
+                Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+            }
+            match port.set_data_bits(set.data_bits) {
+                Ok(_) => {},
+                Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+            }
+            match port.set_parity(set.parity) {
+                Ok(_) => {},
+                Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+            }
+            match port.set_stop_bits(set.stop_bits) {
+                Ok(_) => {},
+                Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+            }
+            match port.set_flow_control(set.flow_ctrl) {
+                Ok(_) => {},
+                Err(msg) => return Err(format!("error: failed to open serial port {} ({})", port_name, msg)),
+            }
+
+            return Ok(port);
+        }
+    }
+}
+
 fn read_str(s: &str) -> Result<Vec<String>, String> { 
     let re = match Regex::new(r#""([^"]+)"|(\S+)"#) {
         Ok(val) => val,
@@ -69,188 +354,15 @@ fn read_str(s: &str) -> Result<Vec<String>, String> {
     Ok(res)
 }
 
-fn set_port_settings(port_name: &str, baud_rate: u32, data_bits: DataBits, parity: Parity, 
-                     stop_bits: StopBits, flow_ctrl: FlowControl, timeout_msec: u64) -> Result<Box<dyn SerialPort>, String> {
-
-    let mut port = match serialport::new(port_name, baud_rate)
-        .timeout(Duration::from_millis(timeout_msec)).open() {
-            Ok(p) => p,
-            Err(msg) => return Err(format!("{}", msg)),
-        };
-
-    port.set_baud_rate(baud_rate).unwrap();
-    port.set_data_bits(data_bits).unwrap();
-    port.set_parity(parity).unwrap();
-    port.set_stop_bits(stop_bits).unwrap();
-    port.set_flow_control(flow_ctrl).unwrap();
-    return Ok(port);
-}
 
 
-fn tx_rx_data<W: std::io::Write>(port_name: &str, 
-                                 mut data_out: String, 
-                                 cmd_writer: &mut BufWriter<W>, 
-                                 data_writer: &mut BufWriter<W>, 
-                                 save_data_flag: bool,
-                                 save_cmd_flag: bool) {
-    use crate::perf::Perf;
-    let mut perf = Perf::new();
-    perf.start();
-    // let port_name = &args[1];
-    let mut port = match set_port_settings(port_name, 19200, 
-                                           DataBits::Eight, 
-                                           Parity::Even, 
-                                           StopBits::One, 
-                                           FlowControl::None, 100) {
-        Ok(set) => {set},
-        Err(msg) => { println!("error while opening com-port ({}): {}", port_name, msg); return }
-    };
 
-    perf.stop_restart("time open port", "ms");
-
-    if save_cmd_flag == true {
-        writeln!(cmd_writer, "{};{};{}", Perf::cur_time("%Y.%m.%d"), 
-                 Perf::cur_time("%H:%M:%S.%f"), data_out.trim()).expect("err");
-    }
-
-    data_out.push_str(std::str::from_utf8(b"\x0D\x0A").unwrap()); // CR + LF
-    match port.write(data_out.as_bytes()) {
-        Ok(_) => {},
-        Err(e) => eprintln!("Error sending data: {}", e),
-    }
-
-    port.flush().unwrap();
-
-    perf.stop_restart("time write to port", "ms");
-
-    let mut reader = BufReader::new(port);
-    let mut s = String::new();
-    reader.read_line(&mut s).unwrap();
-    if s.len() > 0 {
-        let data = format!("{}: {}", Perf::cur_time("%H:%M:%S.%f"), s.trim());
-        println!("{}", data);
-        if save_data_flag == true {
-            writeln!(data_writer, "{}", 
-                     format!("{};{};{}", 
-                             Perf::cur_time("%Y.%m.%d"), 
-                             Perf::cur_time("%H:%M:%S.%f"), 
-                             s.trim()))
-                .expect("err");
-        }
-    }
-
-    perf.stop("time for receive data", "ms");
-
-    // let mut buffer = Vec::new();
-    // match port.read_to_end(&mut buffer) {
-    //     Ok(_) => {
-    //         if buffer.len() > 0 {
-    //             let data = format!("{}: {:?}", cur_time("%H:%M:%S"), buffer);
-    //             println!("{}", data);
-    //             if save_data_flag == true {
-    //                 writeln!(data_writer, "{}", 
-    //                          format!("{};{};{}", 
-    //                          cur_time("%Y.%m.%d"), 
-    //                          cur_time("%H:%M:%S"), 
-    //                          String::from_utf8(buffer).expect("msg")))
-    //                     .expect("err");
-    //             }
-    //         }
-    //     },
-    //     Err(msg) => eprintln!("{}", msg),
-    // }
-
-    // let mut cnt: u32 = 0;
-    // let mut i = 0;
-    // let mut buf: String = String::new();
-
-    // let start = Utc::now(); 
-    // let mut timeout_flag = false;
-
-    // let mut delta1 = 0;
-    // while cnt == 0 {
-    //     cnt = match port.bytes_to_read() {
-    //         Ok(c) => c,
-    //         Err(msg) => { println!("{}", msg); return; }
-    //     };
-    //     let delta = Utc::now() - start;
-    //     delta1 =  delta.num_microseconds().unwrap()/1000;
-    //     if delta1 > timeout_ms {
-    //         println!("timeout: {}", delta1);
-    //         timeout_flag = true;
-    //         break;
-    //     };
-    // }
-
-    // println!("time (ms): {}", delta1);
-
-    // // println!("time (ms): {:?}", delta.num_microseconds().unwrap()/1000);
-
-    // if timeout_flag == false {
-    //     while i < 500000 {
-    //         // thread::sleep(time::Duration::from_millis(10));
-    //         i += 1;
-    //         let mut buffer = [0u8; 4096];
-
-    //         cnt = match port.bytes_to_read() {
-    //             Ok(c) => c,
-    //             Err(msg) => { println!("{}", msg); return; }
-    //         };
-
-    //         if cnt > 0 {
-    //             match port.read(&mut buffer) {
-    //                 Ok(count) => {
-    //                     let s = std::str::from_utf8(&buffer[..count]).unwrap();
-    //                     buf.push_str(s);
-    //                     println!("{}", s);
-    //                 },
-
-    //                 Err(ref e) if e.kind() == io::ErrorKind::TimedOut => { println!("timeout!"); },
-    //                 Err(e) => eprintln!("error reading from port ({}): {}", port_name, e),
-    //             }
-    //         }
-    //         else {}
-    //     }
-
-    // }
-
-
-    // if buf.len() > 0 {
-    //     let data = format!("{}: {:?}", cur_time("%H:%M:%S"), buf);
-    //     println!("{}", data);
-    //     if save_data_flag == true {
-    //         writeln!(data_writer, "{};{};{}", cur_time("%Y.%m.%d"), cur_time("%H:%M:%S"), buf.trim()).expect("err");
-    //     }
-    // }
-
-}
 
 fn main() {
     use crate::perf::Perf;
+    use crate::uartTransact::*;
     let mut perf = Perf::new();
 
-    let data_log_path = "../log/data.log";
-    let file = OpenOptions::new()
-        .write(true)
-        .append(true)
-        .open(data_log_path)
-        .expect("error opening file ");
-
-    let mut data_writer = BufWriter::new(file);
-
-    let data_log_path = "../log/cmd.log";
-    let file = OpenOptions::new()
-        .write(true)
-        .append(true)
-        .open(data_log_path)
-        .expect("error opening file ");
-
-    let mut cmd_writer = BufWriter::new(file);
-
-    let mut save_data_flag = false;
-    let mut save_cmd_flag = false;
-
-    let timeout_ms = 1000;
     let fname_hist = "../settings/cmd_history.log".to_string();
     let mut editor = Editor::<()>::new();
     if editor.load_history(&fname_hist).is_err() {
@@ -281,6 +393,7 @@ fn main() {
 
         editor.add_history_entry(&s);
 
+
         let args = match read_str(&s) {
             Ok(arg) => arg,
             Err(msg) => { 
@@ -296,26 +409,12 @@ fn main() {
         if cmd_head.contains("exit") { break; }
         else if cmd_head.contains("help") {
             println!("Serial port terminal supports the following commands:");
-            println!("exit - excecute quit from this program");
-            println!("help - explain how to use this program");
-            println!("show_ports - shows all available serial ports");
-            println!("send <port name> <data> - sends specified <data> to <port name>");
-            println!("send_loop <port name> <data> <count times>  <period in msec> - sends specified <data> to <port name> in loop mode: <count times> times with period specified in <period in msec> ");
-            println!("open_port <port name> <speed> <data bits> <parity> <stop bits> <flow control> - opens specified <port name> with specified settings");
-            println!("save_data_log <enable/disable>");
-            println!("save_cmd_log <enable/disable>");
-        }
-        else if cmd_head.contains("save_data_log") {
-            if args_cnt != 2 { eprintln!("Error while parse command! {}", "arguments count must be 1"); }
-
-            if args[1].contains("enable") { save_data_flag = true; }
-            else { save_data_flag = false; }
-        }
-        else if cmd_head.contains("save_cmd_log") {
-            if args_cnt != 2 { eprintln!("Error while parse command! {}", "arguments count must be 1"); }
-
-            if args[1].contains("enable") { save_cmd_flag = true; }
-            else { save_cmd_flag = false; }
+            println!("\nexit - excecute quit from this program");
+            println!("\nhelp - explain how to use this program");
+            println!("\nshow_ports - shows all available serial ports");
+            println!("\nsend <port_name> <data> - sends specified <data>");
+            println!("\nsend_loop <port name> <data> <count times>  <period in msec> \n\tsends specified <data> to <port name> in loop mode: <count times> times with period specified in <period in msec> ");
+            println!("\nopen_port <port name> <speed> <data bits: 5, 6, 7, 8> <parity: None, Even, Odd> <stop bits: 1, 2> <flow control: None, Software, Hardware> <timeout_ms> <transaction type: tx, rx, tx_rx, rx_tx> <save commands and data to file: true, false>.\n\tExample1: open_port /dev/ttyUSB0 9600 8 Even 1 None 1000 tx_rx true");
         }
         else if cmd_head.contains("show_ports") {
             match serialport::available_ports() {
@@ -330,12 +429,28 @@ fn main() {
         else if cmd_head == "send" {
             if args_cnt != 3 { eprintln!("Error while parse command! {}", "arguments count must be 2"); }
             else {
-                tx_rx_data(&args[1], 
-                           args[2].clone(), 
-                           &mut cmd_writer, 
-                           &mut data_writer, 
-                           save_data_flag,
-                           save_cmd_flag);
+                let port_name = &args[1];
+                let timeout: u64 = 200;
+                let port_set = PortSettings_t::new(9600, 8, "None", 1, "None", timeout).unwrap();
+                let save_data_flag_ = true;
+                let save_cmd_flag_ = true;
+                let trans_type = "tx_rx";
+
+                let mut uartTrans = UartTransact::new(trans_type, port_name, 
+                                                      port_set, save_data_flag_, save_cmd_flag_).unwrap(); 
+
+                let mut perf = Perf::new();
+                perf.start();
+                let mut data_out = args[2].clone();
+                data_out.push_str(std::str::from_utf8(b"\x0D\x0A").unwrap()); // CR + LF
+
+                uartTrans.addPacketForTx(data_out.clone(), data_out.len() as u32).unwrap();
+                uartTrans.startTransact().unwrap();
+
+                let s = uartTrans.getReceivedPacket();
+                let data = format!("{}: {}", Perf::cur_time("%H:%M:%S.%f"), s.trim());
+                println!("{}", data);
+                perf.stop("time for transaction", "mks");
             }
         }
         else if cmd_head == "send_loop" {
@@ -344,30 +459,33 @@ fn main() {
                 let cnt = args[3].parse::<u32>().unwrap();
                 let period = args[4].parse::<u64>().unwrap();
                 let mut i = 0;
-                while (i < cnt) {
+                while i < cnt {
                     i += 1;
-                    tx_rx_data(&args[1], 
-                           args[2].clone(), 
-                           &mut cmd_writer, 
-                           &mut data_writer, 
-                           save_data_flag,
-                           save_cmd_flag);
-                    
+                    let mut data_out = args[2].clone();
                     thread::sleep(time::Duration::from_millis(period));
                 }
             }
         }
-        else if cmd_head.contains("open port") {
+        else if cmd_head.contains("open_port") {
 
-            if args_cnt != 8 { eprintln!("Error while parse command! {}", "arguments count must be 8"); }
+            if args_cnt != 10 { eprintln!("Error while parse command! {}", "arguments count must be 9"); }
             else {
-                // println!("open port <port name> <speed> <data bits> <parity> <stop bits> <flow control> - opens specified <port name> with specified settings");
-                // let port_name = args[2].clone();
-                // let speed = args[3].clone();
-                // let data_bits = args[4].clone();
-                // let parity = args[5].clone();
-                // let stop_bits = args[6].clone();
-                // let flow_ctrl = args[7].clone();
+                let port_name = &args[1];
+                let speed = args[3].parse::<u32>().unwrap();
+                let data_bits = args[3].parse::<u8>().unwrap();
+                let parity = &args[4];
+                let stop_bits = args[5].parse::<u8>().unwrap();
+                let flow_ctrl = &args[6];
+                let timeout = args[7].parse::<u64>().unwrap();
+                let trans_type = &args[8];
+                let save_data_flag = args[9].parse::<bool>().unwrap(); 
+                let save_cmd_flag = save_data_flag; 
+
+                let port_set = PortSettings_t::new(speed, data_bits, parity, stop_bits, 
+                                                   flow_ctrl, timeout).unwrap();
+
+                let mut uartTrans = UartTransact::new(trans_type, &port_name, 
+                                              port_set, save_data_flag, save_cmd_flag).unwrap(); 
             }
         }
     }
@@ -377,3 +495,93 @@ fn main() {
     // drop(port1);
 
 }
+
+fn print_type_of<T>(_: &T) {
+    println!("{}", std::any::type_name::<T>());
+}
+
+
+// perf.stop("time for transaction", "mks");
+
+// let mut buffer = Vec::new();
+// match port.read_to_end(&mut buffer) {
+//     Ok(_) => {
+//         if buffer.len() > 0 {
+//             let data = format!("{}: {:?}", cur_time("%H:%M:%S"), buffer);
+//             println!("{}", data);
+//             if save_data_flag == true {
+//                 writeln!(data_writer, "{}", 
+//                          format!("{};{};{}", 
+//                          cur_time("%Y.%m.%d"), 
+//                          cur_time("%H:%M:%S"), 
+//                          String::from_utf8(buffer).expect("msg")))
+//                     .expect("err");
+//             }
+//         }
+//     },
+//     Err(msg) => eprintln!("{}", msg),
+// }
+
+// let mut cnt: u32 = 0;
+// let mut i = 0;
+// let mut buf: String = String::new();
+
+// let start = Utc::now(); 
+// let mut timeout_flag = false;
+
+// let mut delta1 = 0;
+// while cnt == 0 {
+//     cnt = match port.bytes_to_read() {
+//         Ok(c) => c,
+//         Err(msg) => { println!("{}", msg); return; }
+//     };
+//     let delta = Utc::now() - start;
+//     delta1 =  delta.num_microseconds().unwrap()/1000;
+//     if delta1 > timeout_ms {
+//         println!("timeout: {}", delta1);
+//         timeout_flag = true;
+//         break;
+//     };
+// }
+
+// println!("time (ms): {}", delta1);
+
+// // println!("time (ms): {:?}", delta.num_microseconds().unwrap()/1000);
+
+// if timeout_flag == false {
+//     while i < 500000 {
+//         // thread::sleep(time::Duration::from_millis(10));
+//         i += 1;
+//         let mut buffer = [0u8; 4096];
+
+//         cnt = match port.bytes_to_read() {
+//             Ok(c) => c,
+//             Err(msg) => { println!("{}", msg); return; }
+//         };
+
+//         if cnt > 0 {
+//             match port.read(&mut buffer) {
+//                 Ok(count) => {
+//                     let s = std::str::from_utf8(&buffer[..count]).unwrap();
+//                     buf.push_str(s);
+//                     println!("{}", s);
+//                 },
+
+//                 Err(ref e) if e.kind() == io::ErrorKind::TimedOut => { println!("timeout!"); },
+//                 Err(e) => eprintln!("error reading from port ({}): {}", port_name, e),
+//             }
+//         }
+//         else {}
+//     }
+
+// }
+
+
+// if buf.len() > 0 {
+//     let data = format!("{}: {:?}", cur_time("%H:%M:%S"), buf);
+//     println!("{}", data);
+//     if save_data_flag == true {
+//         writeln!(data_writer, "{};{};{}", cur_time("%Y.%m.%d"), cur_time("%H:%M:%S"), buf.trim()).expect("err");
+//     }
+// }
+