diff --git a/application/tom_modem/Makefile b/application/tom_modem/Makefile
index 31b0a72..c65cd84 100644
--- a/application/tom_modem/Makefile
+++ b/application/tom_modem/Makefile
@@ -2,8 +2,8 @@ include $(TOPDIR)/rules.mk
 include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:= tom_modem
-PKG_RELEASE:=beta-1
-PKG_VERSION:=0.9.1
+PKG_RELEASE:=beta-2
+PKG_VERSION:=0.9.2
 
 include $(INCLUDE_DIR)/package.mk
 
@@ -13,6 +13,12 @@ define Package/$(PKG_NAME)
   TITLE:=Fujr Modem Communite Tool
 endef
 
+define Package/$(PKG_NAME)/config
+	config PACKAGE_$(PKG_NAME)_EARLY_RETURN
+		bool "Early return"
+		default y
+endef
+
 define Package/$(PKG_NAME)/description
   Modem Communite Tool for 5G modem (By Fujr)
 endef
@@ -23,6 +29,9 @@ define Build/Prepare
 endef
 
 define Build/Compile
+	ifdef CONFIG_PACKAGE_$(PKG_NAME)_EARLY_RETURN
+		TARGET_CFLAGS+=-DEARLY_RETURN
+	else
 	$(MAKE) -C $(PKG_BUILD_DIR) \
 		$(TARGET_CONFIGURE_OPTS) CFLAGS="$(TARGET_CFLAGS)"
 endef
diff --git a/application/tom_modem/src/Makefile b/application/tom_modem/src/Makefile
index 85f4a61..35bb93e 100644
--- a/application/tom_modem/src/Makefile
+++ b/application/tom_modem/src/Makefile
@@ -1,8 +1,8 @@
 TARGET = tom_modem
 
-CFLAGS = -Wall  -Ipdu_lib
+CFLAGS ?= -Wall  -Iextlib
 
-SRCS = main.c utils.c pdu_lib/pdu.c pdu_lib/ucs2_to_utf8.c
+SRCS = main.c utils.c extlib/pdu.c extlib/ucs2_to_utf8.c
 
 OBJS = $(SRCS:.c=.o)
 
@@ -19,6 +19,8 @@ clean:
 .PHONY:clean
 clean:
 	rm -rf *.o *.*~ *~ *.swap $(all)
+	rm -rf $(TARGET)
+	rm -rf extlib/*.o
 depend:
 	$(CC) $(CFLAGS) -MM $(SRCS) > .depend
 
diff --git a/application/tom_modem/src/pdu_lib/pdu.c b/application/tom_modem/src/extlib/pdu.c
similarity index 100%
rename from application/tom_modem/src/pdu_lib/pdu.c
rename to application/tom_modem/src/extlib/pdu.c
diff --git a/application/tom_modem/src/pdu_lib/pdu.h b/application/tom_modem/src/extlib/pdu.h
similarity index 100%
rename from application/tom_modem/src/pdu_lib/pdu.h
rename to application/tom_modem/src/extlib/pdu.h
diff --git a/application/tom_modem/src/pdu_lib/pdu_decoder.c b/application/tom_modem/src/extlib/pdu_decoder.c
similarity index 100%
rename from application/tom_modem/src/pdu_lib/pdu_decoder.c
rename to application/tom_modem/src/extlib/pdu_decoder.c
diff --git a/application/tom_modem/src/pdu_lib/ucs2_to_utf8.c b/application/tom_modem/src/extlib/ucs2_to_utf8.c
similarity index 100%
rename from application/tom_modem/src/pdu_lib/ucs2_to_utf8.c
rename to application/tom_modem/src/extlib/ucs2_to_utf8.c
diff --git a/application/tom_modem/src/main.c b/application/tom_modem/src/main.c
index bf3775a..e659fd6 100644
--- a/application/tom_modem/src/main.c
+++ b/application/tom_modem/src/main.c
@@ -1,27 +1,8 @@
-#include "modem_types.h"
+
 #include "main.h"
-#include "utils.h"
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <termios.h>
-#include <signal.h>
-#include <sys/select.h>
-#include <errno.h>
-
-FILE *fdi;             // file descriptor for input
-FILE *fdo;             // file descriptor for output
-int tty_fd;            // file descriptor for tty device
 
+FDS_T s_fds;
 PROFILE_T s_profile;   // global profile     
-char *self_name; // program name
-void _timeout(int signo)
-{
-    err_msg("Exit with Signal %d", signo);
-    kill(getpid(), SIGINT);
-}
 
 int parse_user_input(int argc, char *argv[], PROFILE_T *profile)
 {
@@ -34,8 +15,8 @@ int parse_user_input(int argc, char *argv[], PROFILE_T *profile)
         option = match_option(argv[opt]);
         if (option == -1)
         {
-            usage();
-            return -1;
+            usage(argv[0]);
+            return INVALID_PARAM;
         }
         opt++;
         switch (option)
@@ -43,72 +24,72 @@ int parse_user_input(int argc, char *argv[], PROFILE_T *profile)
         case AT_CMD:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->at_cmd = argv[opt++];
             break;
         case TTY_DEV:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->tty_dev = argv[opt++];
             break;
         case BAUD_RATE:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->baud_rate = atoi(argv[opt++]);
             break;
         case DATA_BITS:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->data_bits = atoi(argv[opt++]);
             break;
         case PARITY:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->parity = argv[opt++];
             break;
         case STOP_BITS:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->stop_bits = atoi(argv[opt++]);
             break;
         case FLOW_CONTROL:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->flow_control = argv[opt++];
             break;
         case TIMEOUT:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->timeout = atoi(argv[opt++]);
             break;
         case OPERATION:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->op = match_operation(argv[opt++]);
             break;
@@ -118,16 +99,16 @@ int parse_user_input(int argc, char *argv[], PROFILE_T *profile)
         case SMS_PDU:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->sms_pdu = argv[opt++];
             break;
         case SMS_INDEX:
             if (!has_more_argv())
             {
-                usage();
-                return -1;
+                usage(argv[0]);
+                return INVALID_PARAM;
             }
             profile->sms_index = atoi(argv[opt++]);
             break;
@@ -153,53 +134,57 @@ int parse_user_input(int argc, char *argv[], PROFILE_T *profile)
     {
         profile->op = AT_OP;
     }
-  
+    return SUCCESS;
 }
-
-int run_op(PROFILE_T *profile)
+int run_op(PROFILE_T *profile,FDS_T *fds)
 {
     switch (profile->op)
     {
     case AT_OP:
-        at(profile);
-        break;
+        return at(profile,fds);
     case SMS_READ_OP:
-        sms_read(profile);
-        break;
+        return sms_read(profile,fds);
     case SMS_SEND_OP:
-        sms_send(profile);
-        break;
+        return sms_send(profile,fds);
     case SMS_DELETE_OP:
-        sms_delete(profile);
-        break;
+        return sms_delete(profile,fds);
     default:
         err_msg("Invalid operation");
-        break;
     }
+    return UNKNOWN_ERROR;
+}
+static void clean_up()
+{
+    if (tcsetattr(s_fds.tty_fd, TCSANOW, &s_fds.old_termios) != 0)
+    {
+        err_msg("Error restoring old tty attributes");
+        return;
+    }
+    dbg_msg("Clean up success");
+    tcflush(s_fds.tty_fd, TCIOFLUSH);
+    if (s_fds.tty_fd >= 0)
+        close(s_fds.tty_fd);
 }
 
 int main(int argc, char *argv[])
 {
-    int ret;
-    // init
-    self_name = argv[0];
     PROFILE_T *profile = &s_profile;
+    FDS_T *fds = &s_fds;
     parse_user_input(argc, argv, profile);
     dump_profile();
-    signal(SIGALRM, _timeout);
-
     // try open tty devices
-    if (open_tty_device(profile))
+    if (tty_open_device(profile,fds))
     {
         err_msg("Failed to open tty device");
-        return -1;
+        return COMM_ERROR;
     }
-    if (run_op(profile))
+    atexit(clean_up);
+    if (run_op(profile,fds))
     {
         err_msg("Failed to run operation %d", profile->op);
-        return -1;
+        kill(getpid(), SIGINT); 
     }
     
     dbg_msg("Exit");
-    return 0;
+    return SUCCESS;
 }
diff --git a/application/tom_modem/src/main.h b/application/tom_modem/src/main.h
index 6a95996..77b1c6e 100644
--- a/application/tom_modem/src/main.h
+++ b/application/tom_modem/src/main.h
@@ -1,7 +1,5 @@
 #ifndef _MAIN_H_
 #define _MAIN_H_
-#include "modem_types.h"
-#include "main.h"
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
@@ -11,23 +9,24 @@
 #include <signal.h>
 #include <sys/select.h>
 #include <errno.h>
+#include "operations.h"
+#include "ttydevice.h"
+#include "modem_types.h"
+#include "utils.h"
 
 #define DEFAULT_TIMEOUT 3
 // 
-extern FILE *fdi;             // file descriptor for input
-extern FILE *fdo;             // file descriptor for output
-extern int tty_fd;            // file descriptor for tty device
+
 extern PROFILE_T s_profile;   // global profile     
-extern char *self_name;       // program name
-extern struct termios oldtio; // old tty setting
 
-extern  int at(PROFILE_T *profile);
 
-extern  int sms_read(PROFILE_T *profile);
+extern  int at(PROFILE_T *profile,FDS_T *fds);
 
-extern  int sms_send(PROFILE_T *profile);
+extern  int sms_read(PROFILE_T *profile,FDS_T *fds);
 
-extern  int sms_delete(PROFILE_T *profile);
+extern  int sms_send(PROFILE_T *profile,FDS_T *fds);
+
+extern  int sms_delete(PROFILE_T *profile,FDS_T *fds);
 
 extern void dump_profile();
 
@@ -35,8 +34,8 @@ extern int match_option(char *option_name);
 
 extern int match_operation(char *operation_name);
 
-extern int open_tty_device(PROFILE_T *profile);
+extern int open_tty_device(PROFILE_T *profile,FDS_T *fds);
 
-extern int usage();
+extern int usage(char* name);
 
 #endif
diff --git a/application/tom_modem/src/modem_types.h b/application/tom_modem/src/modem_types.h
index 6c19849..670d028 100644
--- a/application/tom_modem/src/modem_types.h
+++ b/application/tom_modem/src/modem_types.h
@@ -1,7 +1,9 @@
 
 #ifndef _MODEM_TYPES_H_
 #define _MODEM_TYPES_H_
-
+#include <stdio.h>
+#include <termios.h>
+#include <time.h>
 //options
 #define AT_CMD_S 'c'
 #define TTY_DEV_S 'd'
@@ -80,12 +82,20 @@ typedef struct _PROFILE {
     int sms_index;
 } PROFILE_T;
 
+
+typedef struct _FDS {
+    int tty_fd;
+    struct termios old_termios;
+    FILE *fdi;
+    FILE *fdo;
+} FDS_T;
+
 typedef struct _SMS {
     int sms_index;
     int sms_lenght;
     int ref_number;
     int segment_number;
-    int timestamp;
+    time_t timestamp;
     int total_segments;
     int type;
     char *sender;
@@ -93,6 +103,15 @@ typedef struct _SMS {
     char *sms_pdu;
 } SMS_T;
 
+enum ERROR_CODES {
+    COMM_ERROR = -1,
+    SUCCESS = 0,
+    KEYWORD_NOT_MATCH,
+    TIMEOUT_WAITING_NEWLINE,
+    INVALID_PARAM,
+    UNKNOWN_ERROR,
+};
+
 enum SMS_CHARSET {
     SMS_CHARSET_7BIT,
     SMS_CHARSET_UCS2
@@ -121,5 +140,5 @@ enum OPERATIONS {
     SMS_DELETE_OP
 };
 
-
+char *self_name; // program name
 #endif
diff --git a/application/tom_modem/src/operations.c b/application/tom_modem/src/operations.c
new file mode 100644
index 0000000..fcf795f
--- /dev/null
+++ b/application/tom_modem/src/operations.c
@@ -0,0 +1,191 @@
+#include "operations.h"
+
+int at(PROFILE_T *profile,FDS_T *fds)
+{
+    int w_ret,r_ret;
+    char output[COMMON_BUF_SIZE] = {0};
+    if (profile->at_cmd == NULL)
+    {
+        err_msg("AT command is empty");
+        return INVALID_PARAM;
+    }
+    w_ret = tty_write(fds->fdo, profile->at_cmd);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    
+    r_ret = tty_read(fds->fdi, output, COMMON_BUF_SIZE,profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error sending AT command, error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return r_ret;
+    }
+    user_msg("%s", output);
+    return SUCCESS;
+}
+int sms_delete(PROFILE_T *profile,FDS_T *fds)
+{
+    int w_ret,r_ret;
+    if (profile->sms_index < 0)
+    {
+        err_msg("SMS index is empty");
+        return INVALID_PARAM;
+    }
+    char *delete_sms_cmd;
+    delete_sms_cmd = (char *)malloc(32);
+    snprintf(delete_sms_cmd, 32, DELETE_SMS, profile->sms_index);
+    w_ret = tty_write(fds->fdo, delete_sms_cmd);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, NULL, COMMON_BUF_SIZE, "OK",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error deleting SMS, error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return COMM_ERROR;
+    }
+    return SUCCESS;
+}
+int sms_read(PROFILE_T *profile,FDS_T *fds)
+{
+    SMS_T *sms_list[SMS_LIST_SIZE];
+    SMS_T *sms;
+    int w_ret,r_ret;
+    char sms_pdu[SMS_BUF_SIZE] = {0};
+    w_ret = tty_write(fds->fdo, SET_PDU_FORMAT);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, NULL, COMMON_BUF_SIZE, "OK",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error setting PDU format , error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return r_ret;
+    }
+    dbg_msg("Set PDU format success");
+    w_ret = tty_write(fds->fdo, READ_ALL_SMS);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, sms_pdu, SMS_BUF_SIZE, "OK",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error reading SMS , error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return r_ret;
+    }
+
+    
+    
+    //遍历 sms_pdu 的每一行
+    char *line = strtok(sms_pdu, "\n");
+    int sms_count = 0;
+    while (line != NULL)
+    {
+        if (strncmp(line, "+CMGL:", 6) == 0)
+        {
+            sms = (SMS_T *)malloc(sizeof(SMS_T));
+            memset(sms, 0, sizeof(SMS_T));
+            char *pdu = strtok(NULL, "\n");
+            sms->sms_pdu = (char *)malloc(strlen(pdu));
+            sms->sender = (char *)malloc(PHONE_NUMBER_SIZE);
+            sms->sms_text = (char *)malloc(SMS_TEXT_SIZE);
+            sms->sms_index = get_sms_index(line);
+            memcpy(sms->sms_pdu, pdu, strlen(pdu));
+            int sms_len = decode_pdu(sms);
+            if (sms_len > 0)
+            {
+                sms_list[sms_count] = sms;
+                sms_count++;
+            }
+            else
+            {
+                dbg_msg("Error decoding sms");
+                destroy_sms(sms);
+            }
+        }
+        line = strtok(NULL, "\n");
+    }
+
+    
+    display_sms_in_json(sms_list,sms_count);
+    // for (int i = 1; i <= sms_count; i++)
+    // {
+    //     dump_sms(sms_list[i]);
+    //     destroy_sms(sms_list[i]);
+    // }
+    dbg_msg("Read SMS success");
+    dbg_msg("%s", sms_pdu);
+    return SUCCESS;
+}
+int sms_send(PROFILE_T *profile,FDS_T *fds)
+{
+    int w_ret,r_ret;
+    if (profile->sms_pdu == NULL)
+    {
+        err_msg("SMS PDU is empty");
+        return INVALID_PARAM;
+    }
+
+    int pdu_len = strlen(profile->sms_pdu);
+    int pdu_expected_len = (pdu_len) / 2 - 1;
+    char *send_sms_cmd;
+    char *write_pdu_cmd;
+    w_ret = tty_write(fds->fdo, SET_PDU_FORMAT);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, NULL, COMMON_BUF_SIZE, "OK",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error setting PDU format , error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return r_ret;
+    }
+    dbg_msg("Set PDU format success");
+    send_sms_cmd = (char *)malloc(32);
+    write_pdu_cmd = (char *)malloc(256);
+    snprintf(send_sms_cmd, 32, SEND_SMS, pdu_expected_len);
+    dbg_msg("Send SMS command: %s", send_sms_cmd); 
+    snprintf(write_pdu_cmd, 256, "%s%c", profile->sms_pdu, 0x1A);
+    dbg_msg("Write PDU command: %s", write_pdu_cmd);
+    w_ret = tty_write(fds->fdo, send_sms_cmd);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, NULL, COMMON_BUF_SIZE, ">",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error sending SMS STEP 1, error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return COMM_ERROR;
+    }
+    usleep(10000);
+    w_ret = tty_write(fds->fdo, write_pdu_cmd);
+    if (w_ret)
+    {
+        return w_ret;
+    }
+    r_ret = tty_read_keyword(fds->fdi, NULL, COMMON_BUF_SIZE, "+CMGS:",profile->timeout);
+    if (r_ret)
+    {
+        dbg_msg("Error sending SMS STEP 2, error code: %d", r_ret);
+        if (r_ret == COMM_ERROR)
+            return COMM_ERROR;
+    }
+
+    free(send_sms_cmd);
+    free(write_pdu_cmd);
+
+
+    return 0;
+}
diff --git a/application/tom_modem/src/operations.h b/application/tom_modem/src/operations.h
new file mode 100644
index 0000000..75531b0
--- /dev/null
+++ b/application/tom_modem/src/operations.h
@@ -0,0 +1,10 @@
+#ifndef OPERATION_H
+#define OPERATION_H
+#include "modem_types.h"
+#include "ttydevice.h"
+#include "utils.h"
+int tty_open_device(PROFILE_T *profile, FDS_T *fds);
+int tty_read(FILE *fdi, char *output, int len, int soft_timeout);
+int tty_read_keyword(FILE *fdi, char *output, int len, char *key_word, int soft_timeout);
+int tty_write(FILE *fdo, char *input);
+#endif
diff --git a/application/tom_modem/src/pdu_lib/Makefile b/application/tom_modem/src/pdu_lib/Makefile
deleted file mode 100644
index 4985007..0000000
--- a/application/tom_modem/src/pdu_lib/Makefile
+++ /dev/null
@@ -1,21 +0,0 @@
-ALL: pdu_decoder
-
-#CROSS_COMPILE=mips-openwrt-linux-
-
-#CC = $(CROSS_COMPILE)gcc
-
-#CFLAGS = -O2
-
-pdu.o:
-	$(CC) $(CFLAGS) -c pdu.c
-pdu_decoder.o:
-	$(CC) $(CFLAGS) -c pdu_decoder.c
-ucs2_to_utf8:
-	$(CC) $(CFLAGS) -c ucs2_to_utf8.c
-pdu_decoder: pdu.o pdu_decoder.o ucs2_to_utf8
-	$(CC) $(CFLAGS) ucs2_to_utf8.o pdu.o pdu_decoder.o -o pdu_decoder
-clean:
-	rm -f *.o pdu_decoder
-test: clean ALL
-	echo "0891683108501405F8240BA10156686616F60008414090912385235C6D4191CF6C4752A860015BC67801FF1A00350030003900360036FF0C4EB2FF0C8BB05F9762BD59566BCF592990FD8981676554E6FF0C611F89C9597D76848BDD63A883507ED960A87684670B53CBFF019884795D60A84E2D5956FF01"|./pdu_decoder
-	echo "0891683108501405F8640BA10156686616F6000841400100957423830608048A3002026B21767B5F556D4191CF6C475373900100356D4191CF5E01FF0853EF63620035004D6D4191CFFF09FF0C731B623394FE63A5FF1A0068007400740070003A002F002F007300680061006B0065002E00730064002E006300680069006E0061006D006F00620069006C0065002E0063006F006D30025C714E1C79FB52A8"|./pdu_decoder
diff --git a/application/tom_modem/src/ttydevice.c b/application/tom_modem/src/ttydevice.c
new file mode 100644
index 0000000..3569985
--- /dev/null
+++ b/application/tom_modem/src/ttydevice.c
@@ -0,0 +1,210 @@
+#include "ttydevice.h"
+static int tty_set_device(PROFILE_T *profile, FDS_T *fds)
+{
+    int baud_rate, data_bits;
+    struct termios tty;
+    baud_rate = profile->baud_rate;
+    data_bits = profile->data_bits;
+    if (tcgetattr(fds->tty_fd, &tty) != 0)
+    {
+        err_msg("Error getting tty attributes");
+        return COMM_ERROR;
+    }
+    memmove(&fds->old_termios, &tty, sizeof(struct termios));
+    cfmakeraw(&tty);
+    tty.c_cflag |= CLOCAL; // 忽略调制解调器控制线，允许本地连接
+    tty.c_cflag |= CREAD;  // 使能接收
+
+    // clear flow control ,stop bits parity
+    tty.c_cflag &= ~CRTSCTS;
+    tty.c_cflag &= ~CSTOPB;
+    tty.c_cflag &= ~PARENB;
+    tty.c_oflag &= ~OPOST;
+    tty.c_cc[VMIN] = 0;
+    tty.c_cc[VTIME] = 1;
+
+    // set data bits 5,6,7,8
+    tty.c_cflag &= ~CSIZE; // 清除数据位设置
+    switch (data_bits)
+    {
+    case 5:
+        tty.c_cflag |= CS5;
+        break;
+    case 6:
+        tty.c_cflag |= CS6;
+        break;
+    case 7:
+        tty.c_cflag |= CS7;
+        break;
+    case 8:
+        tty.c_cflag |= CS8;
+        break;
+    default:
+        tty.c_cflag |= CS8;
+        break;
+    }
+
+    // set baud rate
+    switch (baud_rate)
+    {
+    case 4800:
+        cfsetspeed(&tty, B4800);
+        break;
+    case 9600:
+        cfsetspeed(&tty, B9600);
+        break;
+    case 19200:
+        cfsetspeed(&tty, B19200);
+        break;
+    case 38400:
+        cfsetspeed(&tty, B38400);
+        break;
+    case 57600:
+        cfsetspeed(&tty, B57600);
+        break;
+    case 115200:
+        cfsetspeed(&tty, B115200);
+        break;
+
+    default:
+        cfsetspeed(&tty, B115200);
+        break;
+    }
+    if (tcsetattr(fds->tty_fd, TCSANOW, &tty) != 0)
+    {
+        err_msg("Error setting tty attributes");
+        return COMM_ERROR;
+    }
+    return SUCCESS;
+}
+int tty_open_device(PROFILE_T *profile,FDS_T *fds)
+{
+    fds->tty_fd = open(profile->tty_dev, O_RDWR | O_NOCTTY);
+    if (fds->tty_fd < 0)
+    {
+        err_msg("Error opening tty device: %s", profile->tty_dev);
+        return COMM_ERROR;
+    }
+
+    if (tty_set_device(profile,fds) != 0)
+    {
+        err_msg("Error setting tty device");
+        return COMM_ERROR;
+    }
+    tcflush(fds->tty_fd, TCIOFLUSH);
+    if (fds->tty_fd >= 0)
+        close(fds->tty_fd);
+    else
+        return COMM_ERROR;
+    fds->tty_fd = open(profile->tty_dev, O_RDWR | O_NOCTTY | O_NONBLOCK);
+    fds->fdi = fdopen(fds->tty_fd, "r");
+    fds->fdo = fdopen(fds->tty_fd, "w");
+    if (fds->fdi == NULL || fds->fdo == NULL)
+    {
+        err_msg("Error opening file descriptor");
+        return COMM_ERROR;
+    }
+
+    if (setvbuf(fds->fdo , NULL, _IOFBF, 0))
+    {
+        err_msg("Error setting buffer for fdi");
+        return COMM_ERROR;
+    }
+
+    if (setvbuf(fds->fdi , NULL, _IOLBF, 0))
+    {
+        err_msg("Error setting buffer for fdi");
+        return COMM_ERROR;
+    }
+    return SUCCESS;
+}
+
+int tty_read(FILE *fdi, char *output, int len, int soft_timeout)
+{
+    return tty_read_keyword(fdi, output, len, NULL, soft_timeout);
+}
+
+int tty_read_keyword(FILE *fdi, char *output, int len, char *key_word, int soft_timeout)
+{
+    char tmp[LINE_BUF] = {0};
+    int msg_len = 0;
+    int read_flag = 0;
+    time_t start_time = time(NULL);
+    int exitcode = TIMEOUT_WAITING_NEWLINE;
+    while (difftime(time(NULL), start_time) < soft_timeout)
+    {
+        if (fgets(tmp, LINE_BUF, fdi))
+        {
+            read_flag = 1;
+            dbg_msg("%s", tmp);
+            if (output != NULL)
+                msg_len += snprintf(output + msg_len, len - msg_len, "%s", tmp);
+
+            if (strncmp(tmp, "OK", 2) == 0 ||
+                strncmp(tmp, "ERROR", 5) == 0 ||
+                strncmp(tmp, "+CMS ERROR:", 11) == 0 ||
+                strncmp(tmp, "+CME ERROR:", 11) == 0 ||
+                strncmp(tmp, "NO CARRIER", 10) == 0 ||
+                (key_word != NULL && strncmp(tmp, key_word, strlen(key_word)) == 0))
+                {
+                    if (key_word != NULL && strncmp(tmp, key_word, strlen(key_word)) == 0)
+                    {
+                        dbg_msg("keyword found");
+                        exitcode = SUCCESS;
+                    }
+                    else if (key_word == NULL)
+                    {
+                        exitcode = SUCCESS;
+                    }
+                    else
+                    {
+                        exitcode = KEYWORD_NOT_MATCH;
+                    }
+                    break;
+                }
+        }
+#ifdef EARLY_RETURN
+        else
+        {
+            if (read_flag > 500){
+                dbg_msg("early return");
+                exitcode = TIMEOUT_WAITING_NEWLINE;
+                break;
+            }
+            if (read_flag){
+                read_flag++;
+            }
+        }
+#endif
+        usleep(1000);
+    }
+    if (read_flag == 0)
+    {
+        exitcode = COMM_ERROR;
+    }
+    return exitcode;
+}
+
+int tty_write(FILE *fdo, char *input)
+{
+    int cmd_len, ret;
+    char *cmd_line;
+    cmd_len = strlen(input) + 3;
+    cmd_line = (char *)malloc(cmd_len);
+    if (cmd_line == NULL)
+    {
+        err_msg("Error allocating memory");
+        return COMM_ERROR;
+    }
+    snprintf(cmd_line, cmd_len, "%s\r\n", input);
+    ret = fputs(cmd_line, fdo);
+    free(cmd_line);
+    fflush(fdo);
+    usleep(100);
+    if (ret < 0)
+    {
+        err_msg("Error writing to tty %d" , ret);
+        return COMM_ERROR;
+    }
+    return SUCCESS;
+}
diff --git a/application/tom_modem/src/ttydevice.h b/application/tom_modem/src/ttydevice.h
new file mode 100644
index 0000000..14b086c
--- /dev/null
+++ b/application/tom_modem/src/ttydevice.h
@@ -0,0 +1,6 @@
+#ifndef TTYDEVICE_H
+#define TTYDEVICE_H
+#include "modem_types.h"
+#include "utils.h"
+int tty_open_device(PROFILE_T *profile,FDS_T *fds);
+#endif
diff --git a/application/tom_modem/src/utils.c b/application/tom_modem/src/utils.c
index d33daa7..36a1a49 100644
--- a/application/tom_modem/src/utils.c
+++ b/application/tom_modem/src/utils.c
@@ -1,7 +1,133 @@
 #include "utils.h"
-#include "pdu_lib/pdu.h"
-struct termios oldtio;
 
+static int char_to_hex(char c)
+{
+    // convert char to hex
+    int is_digit, is_lower, is_upper;
+    is_digit = c - '0';
+    is_lower = c - 'a' + 10;
+    is_upper = c - 'A' + 10;
+    if (is_digit >= 0 && is_digit <= 9)
+    {
+        return is_digit;
+    }
+    else if (is_lower >= 10 && is_lower <= 15)
+    {
+        return is_lower;
+    }
+    else if (is_upper >= 10 && is_upper <= 15)
+    {
+        return is_upper;
+    }
+    else
+    {
+        return -1;
+    }
+}
+int decode_pdu(SMS_T *sms)
+{
+    char sms_text[SMS_TEXT_SIZE] = {0};
+    int tp_dcs;
+    int skip_bytes;
+    int pdu_str_len;
+    unsigned char hex_pdu[SMS_PDU_HEX_SIZE] = {0};
+    pdu_str_len = strlen(sms->sms_pdu);
+    for (int i = 0; i < pdu_str_len; i += 2)
+    {
+        hex_pdu[i / 2] = char_to_hex(sms->sms_pdu[i]) << 4;
+        hex_pdu[i / 2] |= char_to_hex(sms->sms_pdu[i + 1]);
+    }
+    int sms_len = pdu_decode(hex_pdu, pdu_str_len/2,
+                             &sms->timestamp,
+                             sms->sender, PHONE_NUMBER_SIZE,
+                             sms_text, SMS_TEXT_SIZE,
+                             &tp_dcs,
+                             &sms->ref_number,
+                             &sms->total_segments,
+                             &sms->segment_number,
+                             &skip_bytes);
+    if (sms_len <= 0)
+    {
+        err_msg("Error decoding pdu");
+        return sms_len;
+    }
+    sms->sms_lenght = sms_len;
+
+    switch ((tp_dcs / 4) % 4)
+    {
+    case 0:
+        { 
+            // GSM 7 bit
+            sms->type = SMS_CHARSET_7BIT;
+            int i;
+            i = skip_bytes;
+            if (skip_bytes > 0)
+                i = (skip_bytes * 8 + 6) / 7;
+            for (; i < strlen(sms_text); i++)
+            {
+                sprintf(sms->sms_text + i, "%c", sms_text[i]);
+            }
+            i++;
+            sprintf(sms->sms_text + i, "%c", '\0');
+            break;
+        }
+    case 2:
+        { 
+            // UCS2
+            sms->type = SMS_CHARSET_UCS2;
+            int offset = 0;
+            for (int i = skip_bytes; i < SMS_TEXT_SIZE; i += 2)
+            {
+                int ucs2_char = 0x000000FF & sms_text[i + 1];
+                ucs2_char |= (0x0000FF00 & (sms_text[i] << 8));
+                unsigned char utf8_char[5];
+                int len = ucs2_to_utf8(ucs2_char, utf8_char);
+                int j;
+                for (j = 0; j < len; j++)
+                {
+                    sprintf(sms->sms_text + offset, "%c", utf8_char[j]);
+                    if (utf8_char[j] != '\0')
+                    {
+                        offset++;
+                    }
+                    
+                }
+            }
+            offset++;
+            sprintf(sms->sms_text + offset, "%c", '\0');
+            break;
+        }
+    default:
+        break;
+    }
+    return sms_len;
+}
+int destroy_sms(SMS_T *sms)
+{
+    if (sms->sms_pdu != NULL)
+    {
+        free(sms->sms_pdu);
+    }
+    if (sms->sender != NULL)
+    {
+        free(sms->sender);
+    }
+    if (sms->sms_text != NULL)
+    {
+        free(sms->sms_text);
+    }
+    free(sms);
+    return SUCCESS;
+}
+int dump_sms(SMS_T *sms)
+{
+    dbg_msg("SMS Index: %d", sms->sms_index);
+    dbg_msg("SMS Text: %s", sms->sms_text);
+    dbg_msg("SMS Sender: %s", sms->sender);
+    dbg_msg("SMS Timestamp: %ld", sms->timestamp);
+    dbg_msg("SMS Segment: %d/%d", sms->segment_number, sms->total_segments);
+    return SUCCESS;
+}
 int match_option(char *option_name)
 {
     char short_option;
@@ -100,7 +226,6 @@ int match_option(char *option_name)
     // if start with '--' then it is a long option
     return -1;
 }
-
 int match_operation(char *operation_name)
 {
 
@@ -120,7 +245,7 @@ int match_operation(char *operation_name)
         case SMS_DELETE_OP_S:
             return SMS_DELETE_OP;
         default:
-            return -1;
+            return INVALID_PARAM;
             break;
         }
     }
@@ -144,174 +269,12 @@ int match_operation(char *operation_name)
         }
         else
         {
-            return -1;
+            return INVALID_PARAM;
         }
     }
+    return SUCCESS;
 }
-
-int open_tty_device(PROFILE_T *profile)
-{
-    tty_fd = open(profile->tty_dev, O_RDWR | O_NOCTTY);
-    if (tty_fd < 0)
-    {
-        err_msg("Error opening tty device: %s", profile->tty_dev);
-        return -1;
-    }
-
-    if (set_tty_device(profile) != 0)
-    {
-        err_msg("Error setting tty device");
-        return -1;
-    }
-    tcflush(tty_fd, TCIOFLUSH);
-    atexit(clean_up);
-    if (tty_fd >= 0)
-        close(tty_fd);
-    tty_fd = open(profile->tty_dev, O_RDWR | O_NOCTTY);
-    fdi = fdopen(tty_fd, "r");
-    fdo = fdopen(tty_fd, "w");
-    if (fdi == NULL || fdo == NULL)
-    {
-        err_msg("Error opening file descriptor");
-        return -1;
-    }
-
-    if (setvbuf(fdo, NULL, _IOFBF, 0))
-    {
-        err_msg("Error setting buffer for fdi");
-        return -1;
-    }
-
-    if (setvbuf(fdi, NULL, _IOLBF, 0))
-    {
-        err_msg("Error setting buffer for fdi");
-        return -1;
-    }
-
-    return 0;
-}
-
-static int set_tty_device(PROFILE_T *profile)
-{
-    int baud_rate, data_bits, stop_bits;
-    char *flow_control;
-    struct termios tty;
-    baud_rate = profile->baud_rate;
-    data_bits = profile->data_bits;
-    stop_bits = profile->stop_bits;
-    flow_control = profile->flow_control;
-    if (tcgetattr(tty_fd, &tty) != 0)
-    {
-        err_msg("Error getting tty attributes");
-        return -1;
-    }
-    memmove(&oldtio, &tty, sizeof(struct termios));
-    cfmakeraw(&tty);
-    tty.c_cflag |= CLOCAL; // 忽略调制解调器控制线，允许本地连接
-    tty.c_cflag |= CREAD;  // 使能接收
-
-    // clear flow control ,stop bits parity
-    tty.c_cflag &= ~CRTSCTS;
-    tty.c_cflag &= ~CSTOPB;
-    tty.c_cflag &= ~PARENB;
-    tty.c_oflag &= ~OPOST;
-    tty.c_cc[VMIN] = 1;
-    tty.c_cc[VTIME] = 0;
-
-    // set data bits 5,6,7,8
-    tty.c_cflag &= ~CSIZE; // 清除数据位设置
-    switch (data_bits)
-    {
-    case 5:
-        tty.c_cflag |= CS5;
-        break;
-    case 6:
-        tty.c_cflag |= CS6;
-        break;
-    case 7:
-        tty.c_cflag |= CS7;
-        break;
-    case 8:
-        tty.c_cflag |= CS8;
-        break;
-    default:
-        tty.c_cflag |= CS8;
-        break;
-    }
-
-    // set baud rate
-    switch (baud_rate)
-    {
-    case 4800:
-        cfsetspeed(&tty, B4800);
-        break;
-    case 9600:
-        cfsetspeed(&tty, B9600);
-        break;
-    case 19200:
-        cfsetspeed(&tty, B19200);
-        break;
-    case 38400:
-        cfsetspeed(&tty, B38400);
-        break;
-    case 57600:
-        cfsetspeed(&tty, B57600);
-        break;
-    case 115200:
-        cfsetspeed(&tty, B115200);
-        break;
-
-    default:
-        cfsetspeed(&tty, B115200);
-        break;
-    }
-    if (tcsetattr(tty_fd, TCSANOW, &tty) != 0)
-    {
-        err_msg("Error setting tty attributes");
-        return -1;
-    }
-    return 0;
-}
-
-int char_to_hex(char c)
-{
-    // convert char to hex
-    int is_digit, is_lower, is_upper;
-    is_digit = c - '0';
-    is_lower = c - 'a' + 10;
-    is_upper = c - 'A' + 10;
-    if (is_digit >= 0 && is_digit <= 9)
-    {
-        return is_digit;
-    }
-    else if (is_lower >= 10 && is_lower <= 15)
-    {
-        return is_lower;
-    }
-    else if (is_upper >= 10 && is_upper <= 15)
-    {
-        return is_upper;
-    }
-    else
-    {
-        return -1;
-    }
-}
-
-static void clean_up()
-{
-    if (tcsetattr(tty_fd, TCSANOW, &oldtio) != 0)
-    {
-        err_msg("Error restoring old tty attributes");
-        return;
-    }
-    dbg_msg("Clean up success");
-    tcflush(tty_fd, TCIOFLUSH);
-    // if (tty_fd >= 0)
-    //     close(tty_fd);
-}
-
-static void escape_json(char *input, char *output)
+void escape_json(char *input, char *output)
 {
     char *p = input;
     char *q = output;
@@ -365,10 +328,9 @@ static void escape_json(char *input, char *output)
     }
     *q = '\0';
 }
-
-int usage()
+int usage(char* name)
 {
-    err_msg("Usage: %s [options]", self_name);
+    err_msg("Usage: %s [options]", name);
     err_msg("Options:");
     err_msg("  -c, --at_cmd <AT command>  AT command");
     err_msg("  -d, --tty_dev <TTY device>  TTY device **REQUIRED**");
@@ -380,12 +342,11 @@ int usage()
     err_msg("  -p, --sms_pdu <sms pdu>  SMS PDU");
     err_msg("  -i, --sms_index <sms index>  SMS index");
     err_msg("Example:");
-    err_msg("  %s -c ATI -d /dev/ttyUSB2 -b 115200 -B 8 -o at #advance at mode set bautrate and data bit", self_name);
-    err_msg("  %s -c ATI -d /dev/ttyUSB2 # normal at mode", self_name);
-    err_msg("  %s -d /dev/mhi_DUN -o r # read sms", self_name);
+    err_msg("  %s -c ATI -d /dev/ttyUSB2 -b 115200 -B 8 -o at #advance at mode set bautrate and data bit", name);
+    err_msg("  %s -c ATI -d /dev/ttyUSB2 # normal at mode", name);
+    err_msg("  %s -d /dev/mhi_DUN -o r # read sms", name);
     exit(-1);
 }
-
 void dump_profile()
 {
     dbg_msg("AT command: %s", s_profile.at_cmd);
@@ -401,332 +362,6 @@ void dump_profile()
     dbg_msg("SMS PDU: %s", s_profile.sms_pdu);
     dbg_msg("SMS index: %d", s_profile.sms_index);
 }
-
-int tty_read(FILE *fdi, char *output, int len, int timeout)
-{
-    return tty_read_keyword(fdi, output, len, timeout, NULL);
-}
-
-int tty_read_keyword(FILE *fdi, char *output, int len, int timeout, char *key_word)
-{
-    int ret, fd;
-    fd_set rfds;
-    struct timeval tv;
-    char tmp[LINE_BUF] = {0};
-    int msg_len = 0;
-    int key_word_len = 0;
-    fd = fileno(fdi);
-    tv.tv_sec = 0;
-    tv.tv_usec = timeout;
-
-    FD_ZERO(&rfds);
-    FD_SET(fd, &rfds);
-    if (key_word != NULL)
-    {
-        key_word_len = strlen(key_word);
-    }
-    while (1)
-    {
-        ret = select(fd + 1, &rfds, NULL, NULL, &tv);
-        if (ret == -1)
-        {
-            if (errno == EINTR)
-            {
-                err_msg("Interrupted by signal");
-                return -1;
-            }
-            err_msg("Error in select");
-            return -1;
-        }
-        else
-        {
-            fgets(tmp, LINE_BUF, fdi);
-            if (output != NULL)
-                msg_len += snprintf(output + msg_len, len - msg_len, "%s", tmp);
-            dbg_msg("%s", tmp);
-        }
-        if (key_word != NULL){
-            if (strncmp(tmp, key_word, key_word_len) == 0)
-            {
-                dbg_msg("Received end sign: %s", tmp);
-                return 0;
-            }
-        }
-        if (strncmp(tmp, "OK", 2) == 0 ||
-            strncmp(tmp, "ERROR", 5) == 0 ||
-            strncmp(tmp, "+CMS ERROR:", 11) == 0 ||
-            strncmp(tmp, "+CME ERROR:", 11) == 0 ||
-            strncmp(tmp, "NO CARRIER", 10) == 0){
-                dbg_msg("Received end sign: %s", tmp);
-                if (key_word == NULL){
-                    return 0;
-                }
-                break;
-            }
-    }
-
-    return -1;
-}
-
-int tty_write(FILE *fdo, char *input)
-{
-    int cmd_len, ret;
-    char *cmd_line;
-    cmd_len = strlen(input) + 3;
-    cmd_line = (char *)malloc(cmd_len);
-    if (cmd_line == NULL)
-    {
-        err_msg("Error allocating memory");
-        return -1;
-    }
-    snprintf(cmd_line, cmd_len, "%s\r\n", input);
-    ret = fputs(cmd_line, fdo);
-    free(cmd_line);
-    fflush(fdo);
-    usleep(100);
-    if (ret < 0)
-    {
-        err_msg("Error writing to tty %d" , ret);
-        return -1;
-    }
-    return 0;
-}
-
-int at(PROFILE_T *profile)
-{
-    char output[COMMON_BUF_SIZE] = {0};
-    if (profile->at_cmd == NULL)
-    {
-        err_msg("AT command is empty");
-        return -1;
-    }
-    alarm(profile->timeout);
-
-    if (tty_write(fdo, profile->at_cmd))
-    {
-        err_msg("Error writing to tty");
-        return -1;
-    }
-
-    if (tty_read(fdi, output, COMMON_BUF_SIZE, 100))
-    {
-        err_msg("Error reading from tty");
-        return -1;
-    }
-    user_msg("%s", output);
-    return 0;
-}
-
-int sms_read(PROFILE_T *profile)
-{
-    SMS_T *sms_list[SMS_LIST_SIZE];
-    SMS_T *sms;
-    char sms_pdu[SMS_BUF_SIZE] = {0};
-    tty_write(fdo, SET_PDU_FORMAT);
-    alarm(profile->timeout);
-    if (tty_read_keyword(fdi, NULL, COMMON_BUF_SIZE, 100, "OK"))
-    {
-        err_msg("Error setting PDU format");
-        return -1;
-    }
-    dbg_msg("Set PDU format success");
-    tty_write(fdo, READ_ALL_SMS);
-    alarm(profile->timeout);
-    if (tty_read_keyword(fdi, sms_pdu, SMS_BUF_SIZE, 100, "OK"))
-    {
-        err_msg("Error reading SMS");
-        return -1;
-    }
-    alarm(0);
-    
-    
-    //遍历 sms_pdu 的每一行
-    char *line = strtok(sms_pdu, "\n");
-    int sms_count = 0;
-    while (line != NULL)
-    {
-        
-        if (strncmp(line, "+CMGL:", 6) == 0)
-        {
-            //解析 line +CMGL: 2,1,,102 获取短信索引
-            sms = (SMS_T *)malloc(sizeof(SMS_T));
-            memset(sms, 0, sizeof(SMS_T));
-            char *pdu = strtok(NULL, "\n");
-            sms->sms_pdu = (char *)malloc(strlen(pdu));
-            sms->sender = (char *)malloc(PHONE_NUMBER_SIZE);
-            sms->sms_text = (char *)malloc(SMS_TEXT_SIZE);
-            sms->sms_index = get_sms_index(line);
-            memcpy(sms->sms_pdu, pdu, strlen(pdu));
-            int sms_len = decode(sms);
-            if (sms_len > 0)
-            {
-                sms_list[sms_count] = sms;
-                sms_count++;
-            }
-            else
-            {
-                destroy_sms(sms);
-            }
-        }
-        line = strtok(NULL, "\n");
-    }
-
-    // for (int i = 1; i <= sms_count; i++)
-    // {
-    //     dump_sms(sms_list[i]);
-    //     //destroy_sms(sms_list[i]);
-    // }
-    display_sms_in_json(sms_list,sms_count);
-    dbg_msg("Read SMS success");
-    dbg_msg("%s", sms_pdu);
-    return 0;
-}
-
-int sms_send(PROFILE_T *profile)
-{
-    if (profile->sms_pdu == NULL)
-    {
-        err_msg("SMS PDU is empty");
-        return -1;
-    }
-
-    int pdu_len = strlen(profile->sms_pdu);
-    int pdu_expected_len = (pdu_len) / 2 - 1;
-    char *send_sms_cmd;
-    char *write_pdu_cmd;
-    tty_write(fdo, SET_PDU_FORMAT);
-    alarm(profile->timeout);
-    if (tty_read_keyword(fdi, NULL, COMMON_BUF_SIZE, 100, "OK"))
-    {
-        err_msg("Error setting PDU format");
-        return -1;
-    }
-    dbg_msg("Set PDU format success");
-    send_sms_cmd = (char *)malloc(32);
-    write_pdu_cmd = (char *)malloc(256);
-    snprintf(send_sms_cmd, 32, SEND_SMS, pdu_expected_len);
-    dbg_msg("Send SMS command: %s", send_sms_cmd); 
-    snprintf(write_pdu_cmd, 256, "%s%c", profile->sms_pdu, 0x1A);
-    dbg_msg("Write PDU command: %s", write_pdu_cmd);
-    free(send_sms_cmd);
-    free(write_pdu_cmd);
-    alarm(0);
-    tty_write(fdo, send_sms_cmd);
-    usleep(10000);
-    tty_write(fdo, write_pdu_cmd);
-    alarm(profile->timeout);
-    if (tty_read_keyword(fdi, NULL, COMMON_BUF_SIZE, 100, "+CMGS:"))
-    {
-        err_msg("Error sending SMS STEP 2");
-        return -1;
-    }
-
-
-
-
-    return 0;
-}
-
-int sms_delete(PROFILE_T *profile)
-{
-    if (profile->sms_index < 0)
-    {
-        err_msg("SMS index is empty");
-        return -1;
-    }
-    char *delete_sms_cmd;
-    delete_sms_cmd = (char *)malloc(32);
-    snprintf(delete_sms_cmd, 32, DELETE_SMS, profile->sms_index);
-    tty_write(fdo, delete_sms_cmd);
-    alarm(profile->timeout);
-    if (tty_read_keyword(fdi, NULL, COMMON_BUF_SIZE, 100, "OK"))
-    {
-        err_msg("Error deleting SMS");
-        return -1;
-    }
-    return 0;
-}
-
-int decode(SMS_T *sms)
-{
-    char sms_text[SMS_TEXT_SIZE] = {0};
-    int tp_dcs;
-    int skip_bytes;
-    int pdu_str_len;
-    time_t sms_time;
-    unsigned char hex_pdu[SMS_PDU_HEX_SIZE] = {0};
-    pdu_str_len = strlen(sms->sms_pdu);
-    for (int i = 0; i < pdu_str_len; i += 2)
-    {
-        hex_pdu[i / 2] = char_to_hex(sms->sms_pdu[i]) << 4;
-        hex_pdu[i / 2] |= char_to_hex(sms->sms_pdu[i + 1]);
-    }
-    int sms_len = pdu_decode(hex_pdu, pdu_str_len/2,
-                             &sms->timestamp,
-                             sms->sender, PHONE_NUMBER_SIZE,
-                             sms_text, SMS_TEXT_SIZE,
-                             &tp_dcs,
-                             &sms->ref_number,
-                             &sms->total_segments,
-                             &sms->segment_number,
-                             &skip_bytes);
-    if (sms_len <= 0)
-    {
-        err_msg("Error decoding pdu");
-        return sms_len;
-    }
-    sms->sms_lenght = sms_len;
-
-    switch ((tp_dcs / 4) % 4)
-    {
-    case 0:
-        { 
-            // GSM 7 bit
-            sms->type = SMS_CHARSET_7BIT;
-            int i;
-            i = skip_bytes;
-            if (skip_bytes > 0)
-                i = (skip_bytes * 8 + 6) / 7;
-            for (; i < strlen(sms_text); i++)
-            {
-                sprintf(sms->sms_text + i, "%c", sms_text[i]);
-            }
-            i++;
-            sprintf(sms->sms_text + i, "%c", '\0');
-            break;
-        }
-    case 2:
-        { 
-            // UCS2
-            sms->type = SMS_CHARSET_UCS2;
-            int offset = 0;
-            for (int i = skip_bytes; i < SMS_TEXT_SIZE; i += 2)
-            {
-                int ucs2_char = 0x000000FF & sms_text[i + 1];
-                ucs2_char |= (0x0000FF00 & (sms_text[i] << 8));
-                unsigned char utf8_char[5];
-                int len = ucs2_to_utf8(ucs2_char, utf8_char);
-                int j;
-                for (j = 0; j < len; j++)
-                {
-                    sprintf(sms->sms_text + offset, "%c", utf8_char[j]);
-                    if (utf8_char[j] != '\0')
-                    {
-                        offset++;
-                    }
-                    
-                }
-            }
-            offset++;
-            sprintf(sms->sms_text + offset, "%c", '\0');
-            break;
-        }
-    default:
-        break;
-    }
-    return sms_len;
-}
-
 int display_sms_in_json(SMS_T **sms,int num)
 {
 
@@ -738,10 +373,10 @@ int display_sms_in_json(SMS_T **sms,int num)
         char escaped_text[SMS_TEXT_SIZE];
         escape_json(sms[i]->sms_text, escaped_text);
         if (sms[i]->ref_number)
-            offset += sprintf(msg_json + offset, "{\"index\":%d,\"sender\":\"%s\",\"timestamp\":%d,\"content\":\"%s\",\"reference\":%d,\"total\":%d,\"part\":%d},",
+            offset += sprintf(msg_json + offset, "{\"index\":%d,\"sender\":\"%s\",\"timestamp\":%ld,\"content\":\"%s\",\"reference\":%d,\"total\":%d,\"part\":%d},",
                           sms[i]->sms_index, sms[i]->sender, sms[i]->timestamp, escaped_text, sms[i]->ref_number, sms[i]->total_segments, sms[i]->segment_number);
         else
-            offset += sprintf(msg_json + offset, "{\"index\":%d,\"sender\":\"%s\",\"timestamp\":%d,\"content\":\"%s\"},",
+            offset += sprintf(msg_json + offset, "{\"index\":%d,\"sender\":\"%s\",\"timestamp\":%ld,\"content\":\"%s\"},",
                           sms[i]->sms_index, sms[i]->sender, sms[i]->timestamp, escaped_text);
     }
     
@@ -752,35 +387,7 @@ int display_sms_in_json(SMS_T **sms,int num)
     }
     offset += sprintf(msg_json + offset, "]}");
     user_msg("%s\n", msg_json);
-    return 0;
+    return SUCCESS;
 
     
 }
-
-int dump_sms(SMS_T *sms)
-{
-    dbg_msg("SMS Index: %d", sms->sms_index);
-    dbg_msg("SMS Text: %s", sms->sms_text);
-    dbg_msg("SMS Sender: %s", sms->sender);
-    dbg_msg("SMS Timestamp: %d", sms->timestamp);
-    dbg_msg("SMS Segment: %d/%d", sms->segment_number, sms->total_segments);
-    return 0;
-}
-
-int destroy_sms(SMS_T *sms)
-{
-    if (sms->sms_pdu != NULL)
-    {
-        free(sms->sms_pdu);
-    }
-    if (sms->sender != NULL)
-    {
-        free(sms->sender);
-    }
-    if (sms->sms_text != NULL)
-    {
-        free(sms->sms_text);
-    }
-    free(sms);
-    return 0;
-}
diff --git a/application/tom_modem/src/utils.h b/application/tom_modem/src/utils.h
index 8758c1b..f71fdff 100644
--- a/application/tom_modem/src/utils.h
+++ b/application/tom_modem/src/utils.h
@@ -1,17 +1,20 @@
 #ifndef _UTILS_H
 #define _UTILS_H
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
 #include <stdlib.h>
+#include <termios.h>
+#include <signal.h>
+#include <sys/select.h>
+#include <errno.h>
 #include "modem_types.h"
-#include "main.h"
+#include "extlib/pdu.h"
+#include "time.h"
 
 extern PROFILE_T s_profile;
-extern FILE *fdi;             // file descriptor for input
-extern FILE *fdo;             // file descriptor for output
-extern int tty_fd;            // file descriptor for tty device
-extern struct termios oldtio; // old tty setting
-
-
+extern FDS_T s_fds;
 
 #define dbg_msg(fmt, args...) do { \
     if (s_profile.debug) { \
@@ -51,9 +54,17 @@ int match_option(char *option_name);
 
 int match_operation(char *operation_name);
 
-int open_tty_device(PROFILE_T *profile);
 
-static int set_tty_device(PROFILE_T *profile);
+int decode_pdu(SMS_T *sms);
 
-static void clean_up();
+
+int tty_read_keyword(FILE *fdi, char *output, int len, char *key_word, int soft_timeout);
+
+int tty_read(FILE *fdi, char *output, int len, int soft_timeout);
+
+int dump_sms(SMS_T *sms);
+
+int destroy_sms(SMS_T *sms);
+
+int display_sms_in_json(SMS_T **sms,int num);
 #endif
diff --git a/docs/tom_modem.cn.md b/docs/tom_modem.cn.md
index d873ce8..38da17a 100644
--- a/docs/tom_modem.cn.md
+++ b/docs/tom_modem.cn.md
@@ -1,5 +1,19 @@
 # 工具介绍
 
+## 更新介绍
+
+### 0.9.2
+
+#### 特性变更
+
+- 在AT通信中，优化了响应处理逻辑：在接收到初始响应后的特定时间内如果没有进一步的响应，则认为通信已结束。这种机制特别适用于那些可能无法正确返回终止符号的命令。（需要注意的是，当ATE功能启用时，命令回显会立即被读取，这可能导致对于执行时间较长的命令提前返回结果。）
+- 在操作执行时，若是模组通讯异常（无返回、护法读写等），会在run_ops函数中返回-1，然后直接发送kill -9 命令（避免close时大量的花销），正常返回则返回0，若是与模组通讯无关的故障（如解析异常）应当返回>0的错误代码
+
+#### 优化
+
+- 更新了超时处理机制，不再依赖alarm信号，而是通过设置阻塞的读写操作，并结合vmin和vtime参数实现超时控制。
+- 实现了组件间的一定程度解耦，提高了系统的灵活性和可维护性。
+
 ## 概述
 
 这个工具是一个 AT 命令行界面，用于与调制解调器进行通信。它支持多种操作，包括发送和读取短信、设置波特率和数据位等。