Protocol NBR 14522

Question

I am developing software for communication with meter via serial port, and I am able to send the commands via serial, follow the codes:

int serial_open(const char *device, int baud)
{   
    struct termios tio;
    int fd = open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);

    memset (&tio, 0, sizeof tio);

    /*
     * Note that `baud' is not an actual baud rate number;
     * it's one of the constants (e. g., `B9600') in <termios.h>
     */
    tcgetattr(fd, &tio);

    cfsetospeed(&tio, baud);
    cfsetispeed(&tio, baud);

    tio.c_cflag = (tio.c_cflag & ~CSIZE) | CS8;     // 8-bit chars
    // disable IGNBRK for mismatched speed tests; otherwise receive break
    // as \000 chars
    tio.c_iflag &= ~IGNBRK;         // disable break processing
    tio.c_lflag = 0;                // no signaling chars, no echo,
                                        // no canonical processing
    tio.c_oflag = 0;                // no remapping, no delays
    tio.c_cc[VMIN]  = 0;            // read doesn't block
    tio.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

    tio.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl

    tio.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
                                        // enable reading
    tio.c_cflag &= ~(PARENB | PARODD);      // shut off parity
    tio.c_cflag |= 0;                   //parity
    tio.c_cflag &= ~CSTOPB;
    tio.c_cflag &= ~CRTSCTS; 

    tcsetattr (fd, TCSANOW, &tio);
    sleep(1);   //Waiting for set serial port

    return fd;
}

uint8_t serial_recv(int fd)
{
    uint8_t byte;
    read(fd, &byte, sizeof byte);
    usleep(1000);

    return byte;
}

void serial_send(int fd, uint8_t byte)
{
    write(fd, &byte, sizeof byte);
    usleep(1000);   //Waiting write byte
}

However the communication protocol says I have to put 0x01 in the serial output and this will be considered stable for 1 second, after that I get ENQ and can send the command.

Meanwhile:

serial_send(fd, 0x01);
sleep(1);

This is not being recognized by the meter, I think it may be some configuration the door opening or I’m misunderstanding the protocol?

Setup of serial 9600 8N1