diff --git a/includes/polling/functions.inc.php b/includes/polling/functions.inc.php
index 3067d1cb73..e96b68c66c 100644
--- a/includes/polling/functions.inc.php
+++ b/includes/polling/functions.inc.php
@@ -1,4 +1,4 @@
-	<?php
+<?php
 
 function poll_sensor($device, $class, $unit)
 {
@@ -370,4 +370,16 @@ function rrd_create_update($device, $name, $def, $val, $step = 300)
     rrdtool_update($rrd, $val);
 }
 
-?>
+function get_main_serial($device) {
+
+    if ($device['os_group'] == 'cisco') {
+        $serial_output = snmp_get_multi($device, "entPhysicalSerialNum.1 entPhysicalSerialNum.1001", "-OQUs", "ENTITY-MIB:OLD-CISCO-CHASSIS-MIB");
+        $serial = "";
+        if (!empty($serial_output[1]['entPhysicalSerialNum'])) {
+            return $serial_output[1]['entPhysicalSerialNum'];
+        } elseif (!empty($serial_output[1001]['entPhysicalSerialNum'])) {
+            return $serial_output[1001]['entPhysicalSerialNum'];
+        }
+    }
+
+}
diff --git a/includes/polling/os/cisco.inc.php b/includes/polling/os/cisco.inc.php
index 61d5dba526..2e12e4466a 100644
--- a/includes/polling/os/cisco.inc.php
+++ b/includes/polling/os/cisco.inc.php
@@ -44,5 +44,5 @@ if ($data[1]['entPhysicalContainedIn'] == "0")
 if(empty($hardware)) {   $hardware = snmp_get($device, "sysObjectID.0", "-Osqv", "SNMPv2-MIB:CISCO-PRODUCTS-MIB"); }
 
 #if(isset($cisco_hardware_oids[$poll_device['sysObjectID']])) { $hardware = $cisco_hardware_oids[$poll_device['sysObjectID']]; }
+$serial = get_main_serial($device);
 
-?>
diff --git a/includes/polling/os/ios.inc.php b/includes/polling/os/ios.inc.php
index de082ec9c2..f98b8f0303 100644
--- a/includes/polling/os/ios.inc.php
+++ b/includes/polling/os/ios.inc.php
@@ -48,5 +48,5 @@ else
 if(empty($hardware)) {   $hardware = snmp_get($device, "sysObjectID.0", "-Osqv", "SNMPv2-MIB:CISCO-PRODUCTS-MIB"); }
 
 #if(isset($cisco_hardware_oids[$poll_device['sysObjectID']])) { $hardware = $cisco_hardware_oids[$poll_device['sysObjectID']]; }
+$serial = get_main_serial($device);
 
-?>
diff --git a/includes/polling/os/iosxr.inc.php b/includes/polling/os/iosxr.inc.php
index 55623809e0..9fca76b553 100644
--- a/includes/polling/os/iosxr.inc.php
+++ b/includes/polling/os/iosxr.inc.php
@@ -11,6 +11,7 @@ else
   # It is not an IOS-XR ... What should we do ?
 }
 
+$serial = get_main_serial($device);
+
 echo("\n".$poll_device['sysDescr']."\n");
 
-?>