C语言实现AT指令ASCII码的拼接处理流程

//将字符串(只包含数字)全部转换成ascii 
int strnumber_to_asciistr(char *dest,const char *src,int len)
{
 int i = 0 ; 
 if(0 == len || NULL == src || NULL == dest)
 return -1; 
 else 
 {
 for(i = 0 ; i < len ; i++,src++)
 {
  if(*src < '0' || *src > '9')
  return -2 ; 
  *dest++ = "0123456789"[*src >> 4];
  *dest++ = "0123456789"[*src & 0x0f];
 }
 *dest = '\0';
 return 0 ;
 }
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//将字符串(只包含数字)全部转换成ascii 
int strnumber_to_asciistr(char *dest,const char *src,int len)
{
 int i = 0 ; 
 if(0 == len || NULL == src || NULL == dest)
 return -1; 
 else 
 {
 for(i = 0 ; i < len ; i++,src++)
 {
  if(*src < '0' || *src > '9')
  return -2 ; 
  *dest++ = "0123456789"[*src >> 4];
  *dest++ = "0123456789"[*src & 0x0f];
 }
 *dest = '\0';
 return 0 ;
 }
}
void Send_Data_To_easyiot(char *__imsi,char *__imei,int property ,int status)
{
  char nb_code_buf[30] = {0};
 char nb_code_buf1[30] = {0};
 char cmd_buf[200] = {0};
 u8 serial = 0 ;
 u8 status_bit = 0 ;
  //IMSI整体转ASCII 
 strnumber_to_asciistr(nb_code_buf,imei,15);
  //IMEI整体转ASCII 
 strnumber_to_asciistr(nb_code_buf1,imsi,15);
 if(property == 1)
 serial = 2 ;
 else 
 serial = 1 ;
 if(status == 0)
 status_bit = 0x3A;
 else 
 status_bit = 0x3B;
 sprintf(cmd_buf,"AT+QLWULDATAEX=57,01F00035000150FFFFFFCE%s%s000001667A5DF5700%d00040%d0001%d%x,0x0100",nb_code_buf,nb_code_buf1,serial,status,status+30,status_bit);
 printf("拼接AT指令::%s\n",cmd_buf);
}
int main(void)
{
 int i ;
 char *_imei = "460111174556744";
 char *_imsi = "867726030069368";
 char imei[31];
 char imsi[31];
 char cmd_buf[150];
 char value = 0 ;
 int property = 0;
 int status = 1 ;
 printf("原来的imei:%s\n",_imei); 
 printf("原来的imsi:%s\n",_imsi); 
 Send_Data_To_easyiot(_imsi,_imei,1,1);
 return 0; 
}