5.8.9.3.1. User Interface 
If you want to set up a consultation hold in the external system,
proceed as follows:
- Initiate the consultation hold in the talking state (incoming or outgoing) in the OpenScape 4000 and dial the OPROVR code.
- Wait for the dial tone of the external system (is not evaluated by the OpenScape 4000)
- Dial the user number in the external system (suffix dialing after grounding).
- Depending on the properties of the external system, either you can transfer the call by going on hook or you must wait until user C picks up.
- Cancel the consultation hold in the external system: initiate the consultation hold (in the OpenScape 4000) and dial the code OPROVR (connection A-B).