boolean is_invalid_STT_command(void)
{
    byte scan;

    for (scan = 3; scan < 15; ++scan)
    {
        if (!is_decimal_digit(spi.data_buffer[scan]))
        {
            return TRUE;
        }
    }

    switch (spi.data_buffer[5])
    {
    case '0':
        if (spi.data_buffer[6] == '0')
        {
            return TRUE;
        }
        else if (spi.data_buffer[6] == '2' && spi.data_buffer[7] == '3')
        {
            return TRUE;
        }
        break;
    case '1':
        if (spi.data_buffer[6] > '2')
        {
            return TRUE;
        }
        break;
    default:
        return TRUE;
    }

    switch (spi.data_buffer[7])
    {
    case '0':
        if (spi.data_buffer[8] == '0')
        {
            return TRUE;
        }
        break;
    case '3':
        if (spi.data_buffer[8] > '1')
        {
            return TRUE;
        }
    case '1':
    case '2':
        break;
    default:
        return TRUE;
    }

    switch (spi.data_buffer[9])
    {
        case '2':
            if (spi.data_buffer[10] > '3')
            {
                return TRUE;
            }
        case '1':
        case '0':
            break;
        default:
            return TRUE;
    }

    if (spi.data_buffer[11] > '5' || spi.data_buffer[13] > '5')
    {
        return TRUE;
    }

    return FALSE;
}