Certain features (e.g. call diversion and callback) do not work in mixed OpenScape 4000/DX-networks because of existing problems with the backwards translation of numbers (e.g. redirection party numbers) from DX-> OpenScape 4000.

The problem can be made worse by numbering schemes that are adopted. For example where 2 companies merge.

Figure 102 shows an example of a network where all the node ID's (i.e. routing codes) are of equal length. The DX network is represented as fictive OpenScape 4000 node 3 (for CLI purposes).

The customer requirement is that they can successfully CF to any extension anywhere in the network. In addition callback to diverted to extensions will also be successfully supported.

The problem with this arrangement, is that the Redirection number is returned to node 1 as 703 #C, i.e. the DX network area code is missing. The OpenScape 4000 does not have the correct routing information if it needs to re-establish the call. In this instance even if the diversion had been performed by the DX, OpenScape 4000 would have incorrect routing information if it needed to perform a callback or circuit optimisation.