function sendFax($documentPath, $faxNumbersArray)
	{
		$from = sessionManager::curentUser('names');
		$msg = date('j F Y H:i:s', time())."\n";
		$msg.= count( $faxNumbersArray )." fax request sent by " . sessionManager::curentUser('names') ." :\nDocument URL : $documentPath\n\n";
	
		foreach ($faxNumbersArray as $faxNumber)
		{
			$command = 'sendfax -f "'.sessionManager::curentUser('email').'" -R -r "'.$from.'" -c "Document" -x "To Company" -d "Recipient@'.$faxNumber.'" '.$documentPath;
			$system = system( escapeshellcmd( $command ), $retval );
			
			$msg .= "Fax number: $faxNumber\n";
			$msg .= "Command: $command\n";		
			$msg .= "Server response: $retval\n\n";
		}
		$msg .= "=======================================================================\n\n";
		error_log($msg,3,'logs/fax_log.txt');
	}

Send Fax with sendfax(1)

PHP