diff --git a/aprs_func.php b/aprs_func.php
index 9669ee1..7e7d47a 100644
--- a/aprs_func.php
+++ b/aprs_func.php
@@ -1,24 +1,17 @@
 <?php
 
 function aprspass ($callsign) { 
-	$stophere = strpos($callsign, '-'); 
-	if ($stophere) $callsign = substr($callsign, 0, $stophere); 
-	$realcall = strtoupper(substr($callsign, 0, 10)); 
-
-	// initialize hash 
-	$hash = 0x73e2; 
-	$i = 0; 
-	$len = strlen($realcall); 
-
-	// hash callsign two bytes at a time 
-	while ($i < $len) { 
-		$hash ^= ord(substr($realcall, $i, 1))<<8; 
-		$hash ^= ord(substr($realcall, $i + 1, 1)); 
-		$i += 2; 
-	} 
+	// drop SSID and use only first 10 characters
+	$call = strtoupper(substr(strtok($callsign,'-'), 0, 10));
+	
+	// make sure station len is even, convert and explode the data
+	$parts = unpack("n*",strlen($call)%2?"$call\x00":$call);
+	
+	// initiate the hash and process the data
+	$hash = 0x73e2; foreach($parts as $part) $hash ^= $part;
 
 	// mask off the high bit so number is always positive 
 	return $hash & 0x7fff; 
 } 
 
-?>
\ No newline at end of file
+?>