PHP M2M CSQ Command Convert to dB and Signal Status

gistfile1.txt

/**
	 * Breakdown of the RSSI return for AT+CSQ command. The return from the command gives a value that needs to be
	 * converted in many instances.
	 *
	 * @link https://m2msupport.net/m2msupport/atcsq-signal-quality/
	 */
$values = array(
		'2'  => array(
			'dB'        => '-109',
			'condition' => 'Marginal'
		),
		'3'  => array(
			'dB'        => '-107',
			'condition' => 'Marginal'
		),
		'4'  => array(
			'dB'        => '-105',
			'condition' => 'Marginal'
		),
		'5'  => array(
			'dB'        => '-103',
			'condition' => 'Marginal'
		),
		'6'  => array(
			'dB'        => '-101',
			'condition' => 'Marginal'
		),
		'7'  => array(
			'dB'        => '-99',
			'condition' => 'Marginal'
		),
		'8'  => array(
			'dB'        => '-97',
			'condition' => 'Marginal'
		),
		'9'  => array(
			'dB'        => '-95',
			'condition' => 'Marginal'
		),
		'10' => array(
			'dB'        => '-93',
			'condition' => 'OK'
		),
		'11' => array(
			'dB'        => '-91',
			'condition' => 'OK'
		),
		'12' => array(
			'dB'        => '-89',
			'condition' => 'OK'
		),
		'13' => array(
			'dB'        => '-87',
			'condition' => 'OK'
		),
		'14' => array(
			'dB'        => '-85',
			'condition' => 'OK'
		),
		'15' => array(
			'dB'        => '-83',
			'condition' => 'Good'
		),
		'16' => array(
			'dB'        => '-81',
			'condition' => 'Good'
		),
		'17' => array(
			'dB'        => '-79',
			'condition' => 'Good'
		),
		'18' => array(
			'dB'        => '-77',
			'condition' => 'Good'
		),
		'19' => array(
			'dB'        => '-75',
			'condition' => 'Good'
		),
		'20' => array(
			'dB'        => '-73',
			'condition' => 'Excellent'
		),
		'21' => array(
			'dB'        => '-71',
			'condition' => 'Excellent'
		),
		'22' => array(
			'dB'        => '-69',
			'condition' => 'Excellent'
		),
		'23' => array(
			'dB'        => '-67',
			'condition' => 'Excellent'
		),
		'24' => array(
			'dB'        => '-65',
			'condition' => 'Excellent'
		),
		'25' => array(
			'dB'        => '-63',
			'condition' => 'Excellent'
		),
		'26' => array(
			'dB'        => '-61',
			'condition' => 'Excellent'
		),
		'27' => array(
			'dB'        => '-59',
			'condition' => 'Excellent'
		),
		'28' => array(
			'dB'        => '-57',
			'condition' => 'Excellent'
		),
		'29' => array(
			'dB'        => '-55',
			'condition' => 'Excellent'
		),
		'30' => array(
			'dB'        => '-53',
			'condition' => 'Excellent'
		),
	);
  
  $rssi   = 18; // Device RSSI value
	$return = $values[ $rssi ]; // Grab the proper array containing the dB and signal condition