diff --git a/app/provision/index.php b/app/provision/index.php
index 16daab0e01..a1dbfdd638 100644
--- a/app/provision/index.php
+++ b/app/provision/index.php
@@ -71,10 +71,15 @@
 	if (empty($mac)){
 		//set the http user agent
 			//$_SERVER['HTTP_USER_AGENT'] = "Yealink SIP-T38G  38.70.0.125 00:15:65:00:00:00";
+			//$_SERVER['HTTP_USER_AGENT'] = "Yealink SIP-T56A  58.80.0.25 001565f429a4"; 
 		//Yealink: 17 digit mac appended to the user agent, so check for a space exactly 17 digits before the end.
 			if (strtolower(substr($_SERVER['HTTP_USER_AGENT'],0,7)) == "yealink" || strtolower(substr($_SERVER['HTTP_USER_AGENT'],0,5)) == "vp530") {
-				$mac = substr($_SERVER['HTTP_USER_AGENT'],-17);
-				$mac = preg_replace("#[^a-fA-F0-9./]#", "", $mac);
+				if (strstr(substr($_SERVER['HTTP_USER_AGENT'],-4), ':')) { //remove colons if they exist
+					$mac = substr($_SERVER['HTTP_USER_AGENT'],-17);
+					$mac = preg_replace("#[^a-fA-F0-9./]#", "", $mac);
+				} else { //take mac as is - fixes T5X series
+					$mac = substr($_SERVER['HTTP_USER_AGENT'],-12);
+				}
 			}
 		//Panasonic: $_SERVER['HTTP_USER_AGENT'] = "Panasonic_KX-UT670/01.022 (0080f000000)"
 			if (substr($_SERVER['HTTP_USER_AGENT'],0,9) == "Panasonic") {