从串行端口上的命令读取响应

Question

我正在编写一个 PHP 应用程序，该应用程序使用串行设备来处理 GSM 调制解调器。这样你就可以通过screen与串口通信，写一个命令就会得到响应。

我使用 PHP 与我的串口通信并使用sleep 在命令之间等待，我使用fopen 和w+ 标志和fwrite 发送命令。我尝试使用fread 函数来检查响应是否存在，但事实并非如此。用 PHP 怎么办？

Answer 1

从概念上讲，如果端口配置正确，f_read 应该可以工作。 https://github.com/Xowap/PHP-Serial

上有一个库 php-serial

这是readPort() 函数：

public function readPort($count = 0)
    {
        if ($this->_dState !== SERIAL_DEVICE_OPENED) {
            trigger_error("Device must be opened to read it", E_USER_WARNING);
            return false;
        }
        if ($this->_os === "linux" || $this->_os === "osx") {
            // Behavior in OSX isn't to wait for new data to recover, but just
            // grabs what's there!
            // Doesn't always work perfectly for me in OSX
            $content = ""; $i = 0;
            if ($count !== 0) {
                do {
                    if ($i > $count) {
                        $content .= fread($this->_dHandle, ($count - $i));
                    } else {
                        $content .= fread($this->_dHandle, 128);
                    }
                } while (($i += 128) === strlen($content));
            } else {
                do {
                    $content .= fread($this->_dHandle, 128);
                } while (($i += 128) === strlen($content));
            }
            return $content;
        } elseif ($this->_os === "windows") {
            // Windows port reading procedures still buggy
            $content = ""; $i = 0;
            if ($count !== 0) {
                do {
                    if ($i > $count) {
                        $content .= fread($this->_dHandle, ($count - $i));
                    } else {
                        $content .= fread($this->_dHandle, 128);
                    }
                } while (($i += 128) === strlen($content));
            } else {
                do {
                    $content .= fread($this->_dHandle, 128);
                } while (($i 

+= 128) === strlen($content));
        }
        return $content;
    }
    return false;
}

(How to Read RS232 Serial Port in PHP like this QBasic Program)