# Tips on Assigning and Changing PBX Numbers

Follow these recommendations to avoid problems when changing the PBX Numbers in the ICP/PBX Networking and Network Elements forms.

- When assigning a new PBX number, always select a new unused value or a number that references an entry in the ICP/PBX Networking form that has no data configured under the IP or ISDN Networking tabs or the PSTN Voice Channel Digits tab.

- Always change the PBX number from the Network Elements (NE) form first. In many cases, changing the PBX number in the NE form is all that is required. If the old PBX number is unique, the NE form will automatically update the corresponding entry in the ICP/PBX Networking form. Since the NE form is shared, the ICP/PBX Networking form is updated on all ICPs of the SDS sharing community.

- For MiVoice Business network elements that are members of a cluster: the PBX number can only be changed from the Network Elements form and only by a element that is part of the same cluster and only when all members of the cluster are SDS sharing and running MCD 5.0.

- For network elements that are not part of a cluster: If the old PBX number is unique, the Network Elements form will automatically update the ICP/PBX Networking form on all ICPs of the SDS sharing community.

- For network elements that are not part of a cluster and have duplicated PBX numbers, the Network Elements form will automatically add a new ICP/PBX Networking entry for the new PBX number and leave the existing ICP/PBX networking entry for the old PBX number. The new entry will have only the Network Element Zone ID stored against the new PBX number. The next step depends on the contents of the ICP/PBX Networking entry for the old PBX number. If the IP Networking IP address matches the network element with the new PBX number, then the entry is updated with the new PBX number. If IP Networking IP address matches the network element with the old PBX number, then the entry stays the same.

If you are changing the PBX number:

- In the ICP/PBX Networking form, select the entry referenced by the old PBX number.

- Click Change, enter the new PBX number, and then Save it.

- Click Data Refresh to update the PBX number in the top half of the form.

- Select the entry for the old PBX number and add the data necessary so that it corresponds to the network element in the Network Elements (NE) form with the same PBX number. If data for the old PBX number must remain unchanged, then select the new PBX number and add the data necessary so that it corresponds with the data for the same PBX number in the NE form.

- Repeat the changes made on each MiVoice Business system in the SDS sharing community (this is necessary since the ICP/PBX Networking form is not SDS shared).