# Calling Party Number (CPN) Substitution

## Description

CPN (Calling Party Number) substitution is typically used to show the customer's corporate name and number for all outgoing calls to the public network. MiVoice Business provides two types of CPN substitution: DID-based and DN-based.

DID-based substitution is used for individual DID numbers or ranges of DID numbers and applies to calls over embedded PRI/DPNSS trunks, embedded BRI trunks ("T" interface only), and SIP trunks.

DN-based substitution is done at the directory number level and applies to calls over embedded PRI/DPNSS trunks and SIP trunks.

You can program both types of substitution on the same system, or within a cluster or network, with priority given to DN-based substitution.

## Conditions and Feature Interactions

- DN-based CPN substitution is not supported for BRI trunks.

- When using DN-based CPN substitution in a network with multiple public network gateways, the gateways must all connect to Central Offices that allow the programmed calling party numbers. Some PRI networks will only allow certain ranges of CPNs and may drop a call if the CPN is disallowed.

- The CPN programmed for DN-based substitution should allow uncompleted calls to return to the call originator or to some other number such as the attendant.

- If this feature is used in a geographically-distributed network of switches, it is possible that although outgoing calls may bypass tolls, such calls returned to extensions provisioned with DN-based CPN Substitution may not.

- The following rules apply to CPN delivery to the public network for forwarded/rerouted calls:

- When an internal call from an extension (Party A) which is provisioned with DN-based CPN is call forwarded to the public network via another Class Of Restriction (COR) extension (Party B), the CPN Substitution programmed for Party A will be passed to the public network not the CPN Substitution programmed for Party B. If Party A has both DID-based and DN-based CPN substitution programmed, the DID-based substitution will be followed.

- When Party A transfers an external call—either from a public or private PRI trunk—to the public network, the DN-based CPN Substitution for Party A will be used if "Display Held Call ID on Transfer" is disabled it its Class of Service. If the option is enabled, then CPN number received from the external trunk will be passed to the public network.

- Support for DN-based CPN substitution requires upgrades to 3300 ICP Release 9.0 UR1 or later on each of the following:

- Calling Party Switch

- Gateway Switch to the Public Network

- PRI Card load.

- You also have the option to configure a unique Default CPN and Default Billing Number for each zone in a cluster. For all SIP trunk calls, if there is no user-specific billing and/or public number (CPN Substitution digits) configured in the Associated Directory Numbers or User and Services Configuration form, MiVoice Business will send these default numbers to a gateway to identify the calling or diverting party and to provide the correct billing number. For more information, see Call Billing for SIP Gateway.

## Programming

NOTE: Program CPN substitution on the controller hosting the DN or, for a resilient DN, on the primary or secondary controller.

To program DID-Based CPN Substitution

1. DID Ranges for CPN Substitution form

- Associate a range of DID numbers with the CPN substitution digits by assigning it an index number.

2. To specify which substitutions apply on a link, do one of the following:

- For embedded PRI and BRI trunks, use the CPN Substitution form ( ) to select an index number for DID Ranges.

- For SIP trunks, use the SIP Peer Profile form ( ) to select an index number for Outgoing DID Ranges.

To program DN-Based CPN Substitution

- Associated Directory Numbers form

- Enter the directory number on which to perform CPN substitution

- Set the Associated Type to CPN Substitution

- Enter the substitution number.

- Class of Service Options form

- Set Non-Prime Public Network Identity to 'Yes' to implement substitution on calls made from non-prime lines.

For both substitution types:

- ISDN Protocol form

- Specify which number to use in CPN substitution for inbound PRI calls forwarded to the public network— the number of the calling party or the number of the forwarding station.

NOTE: These digits are sent whether the CO
See Central Office or Telephone Exchange. allows them or not. It is the System Administrator's responsibility to ensure that the digits programmed in the Associated Digits field of the Associated Directory Numbers form ( ) are acceptable to the CO.

## Device Support

Not applicable

## Operation

None