Read response from command on serial port - php

Question

I am programming a PHP application that uses a serial device to do stuff with GSM modem. So you can communicate with the serial port via screen and you would get a response when you write a command.
I use PHP to communicate with my serial port and use sleep to wait between the commands, I se fopen with w+ flags and fwrite to send the commands. I tried using the fread function to check if the response is there, but it wasn't. How could that be done in PHP?

Answer 1

conceptually f_read should work if the port is configured correctly. there is a library php-serial on https://github.com/Xowap/PHP-Serial
this is the readPort() function :
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 )