diff --git a/includes/callback.php b/includes/callback.php
index 0462461fcb..5039f648dc 100644
--- a/includes/callback.php
+++ b/includes/callback.php
@@ -80,7 +80,7 @@ if ($enabled == 1) {
     // sanitize sysDescr
     $device_info = array_map(function ($entry) {
         // remove hostnames from linux and macosx
-        $entry['sysDescr'] = preg_replace_callback('/^(Linux |Darwin )[A-Za-z0-9._\-]+ ([0-9.]{5,9})/', function ($matches) {
+        $entry['sysDescr'] = preg_replace_callback('/^(Linux |Darwin |FreeBSD )[A-Za-z0-9._\-]+ ([0-9.]{3,9})/', function ($matches) {
             return $matches[1] . 'hostname ' .$matches[2];
         }, $entry['sysDescr']);
 
diff --git a/includes/discovery/sensors/frequency/rfc1628.inc.php b/includes/discovery/sensors/frequency/rfc1628.inc.php
index 14a9b5af2a..6fd2937b35 100644
--- a/includes/discovery/sensors/frequency/rfc1628.inc.php
+++ b/includes/discovery/sensors/frequency/rfc1628.inc.php
@@ -21,19 +21,23 @@ for ($i = 1; $i <= $numPhase; $i++) {
 }
 
 $freq_oid = '.1.3.6.1.2.1.33.1.4.2.0';
-$descr    = 'Output';
-$divisor = get_device_divisor($device, $pre_cache['poweralert_serial'], 'frequency', $freq_oid);
-$current  = (snmp_get($device, $freq_oid, '-Oqv') / $divisor);
-$type     = 'rfc1628';
+$current_freq  = snmp_get($device, $freq_oid, '-Oqv');
+if (is_numeric($current_freq)) {
+    $descr    = 'Output';
+    $divisor = get_device_divisor($device, $pre_cache['poweralert_serial'], 'frequency', $freq_oid);
+    $type     = 'rfc1628';
+    $index = '4.2.0';
 
-$index = '4.2.0';
-discover_sensor($valid['sensor'], 'frequency', $device, $freq_oid, $index, $type, $descr, $divisor, '1', null, null, null, null, $current);
+    discover_sensor($valid['sensor'], 'frequency', $device, $freq_oid, $index, $type, $descr, $divisor, 1, null, null, null, null, $current_freq / $divisor);
+}
 
 $freq_oid = '.1.3.6.1.2.1.33.1.5.1.0';
-$descr    = 'Bypass';
-$divisor = get_device_divisor($device, $pre_cache['poweralert_serial'], 'frequency', $freq_oid);
-$current  = (snmp_get($device, $freq_oid, '-Oqv') / $divisor);
-$type     = 'rfc1628';
+$current_freq  = snmp_get($device, $freq_oid, '-Oqv');
+if (is_numeric($current_freq)) {
+    $descr    = 'Bypass';
+    $divisor = get_device_divisor($device, $pre_cache['poweralert_serial'], 'frequency', $freq_oid);
+    $type     = 'rfc1628';
+    $index = '5.1.0';
 
-$index = '5.1.0';
-discover_sensor($valid['sensor'], 'frequency', $device, $freq_oid, $index, $type, $descr, $divisor, '1', null, null, null, null, $current);
+    discover_sensor($valid['sensor'], 'frequency', $device, $freq_oid, $index, $type, $descr, $divisor, 1, null, null, null, null, $current_freq / $divisor);
+}