diff --git a/gdtf-spec.md b/gdtf-spec.md
index 07ae9da4..0fe530ee 100644
--- a/gdtf-spec.md
+++ b/gdtf-spec.md
@@ -2078,6 +2078,7 @@ currently defined XML attributes of channel function are specified in
 | ModeMaster         | [Node](#user-content-attrtype-node )         | Optional. Link to DMX Channel or Channel Function; Starting point DMX mode.                                                                                   |
 | ModeFrom           | [DMXValue](#user-content-attrtype-dmxvalue ) | Only used together with ModeMaster; DMX start value; Default value: 0/1                                                                                       |
 | ModeTo             | [DMXValue](#user-content-attrtype-dmxvalue ) | Only used together with ModeMaster; DMX end value; Default value: 0/1                                                                                         |
+| ModeDefault        | [DMXValue](#user-content-attrtype-dmxvalue ) | Only used together with ModeMaster; DMX default value for the DMX Channel or Channel Function linked via ModeMaster. This value is applied only if the DMX value cannot be determined based on physical value or wheel slot index; Default value: 0/1                                                                                         |
 | DMXProfile         | [Node](#user-content-attrtype-node )         | Optional link to DMX Profile; Starting point: DMX Profile Collect                                                                                             |
 | Min                | [Float](#user-content-attrtype-float )       | Minimum Physical Value that will be used for the DMX Profile. Default: Value from PhysicalFrom                                                                |
 | Max                | [Float](#user-content-attrtype-float )       | Maximum Physical Value that will be used for the DMX Profile. Default: Value from PhysicalTo                                                                  |