diff --git a/lib/NGCP/Panel/Role/API/PbxDeviceModels.pm b/lib/NGCP/Panel/Role/API/PbxDeviceModels.pm
index 4fe6729172..1cc01cb86b 100644
--- a/lib/NGCP/Panel/Role/API/PbxDeviceModels.pm
+++ b/lib/NGCP/Panel/Role/API/PbxDeviceModels.pm
@@ -82,6 +82,7 @@ sub resource_from_item {
                 labelpos => $key->position,
             };
         }
+        $r->{num_lines} = @{ $r->{keys} };
 
         push @{ $resource{linerange} }, $r;
     }