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The Account Codes Service allows the subscriber to enter a special digit sequence (the account code) that is reflected in the billing record generated for the call. This enables the tracking and categorization of calls made or received by the subscriber. Account codes are managed by a Business Group Administrator and can be from 2 to 14

digits long. Account codes can be variable length, or configured to be a fixed length as a part of the configuration data for the service.

The subscriber may associate an account-code with a session using one of several methods. In the first method, the subscriber enters a vertical service code (*VSC) to initiate the account code service. The service then provides recall dial tone which prompts the subscriber to enter the account code. The end of the account code is indicated in one of three methods:

• by either having the subscriber enter a ‘#’ digit

• the expiry of interdigital timing

• when sufficient account code digits have been entered, in scenarios where fixed length account codes are configured.

After the account code has been entered, dial tone is provided to the subscriber and they can proceed with dialing the called DN for the session.

In the second method, the subscriber can perform a mid-call activation of the service. When this is done with an analogue POTS set, the subscriber initiates the account code service by entering a switch-hook flash on an active call. After receiving recall dial tone, the subscriber dials the VSC associated with the service. The service provides recall dial tone, and the subscriber enters an account code. The end of the account code is determined the same as in the first method. After the account code has been entered, dial tone is provided to the subscriber, and they can take one of two options.

• If the intent is to associate an account code with the initial leg of the call, then the user may enter a switch-hook flash and be re-connected to the initial call. The account code entered will be included in the billing record for the call.

• If the intent is to have the account code apply to the second leg of a three-way call, then the user can proceed with dialing the DN of the party to be added to the conference. From this point forward, the call proceeds as a normal three-way call. The account code entered will be included in the billing leg for the second leg of the three-way call.

Mid-call activation can also be performed on a more sophisticated SIP business set in such a way that it does not interrupt the session that is in progress. The business set would provide an interface for the user to specify the account code and indicate which session should be associated with the account code. The application server can be notified of this with call control signaling, in such a way that the active session does not need to be placed on hold. A third method for initiating the account code service is by configuring the user’s profile or dialing plan to indicate that account codes are mandatory either on all calls, or on all calls to specific destinations. In these scenarios, the user begins by dialing the destination DN. After the application server determines that an account code is mandatory, dial tone is re-applied to the user’s line which prompts them to enter the account code digits.

A web portal may provide a BG administrator with the ability to define account codes attributes for the BG (length, fixed or variable) and manage the user profile for the third method.

The service does not provide validation of the account codes, aside from insuring that account codes have a sufficient number of digits if fixed-length account codes are configured. If an invalid account code is detected, it is flagged in the billing record associated with the call.

The Telcordia reference for this service is [GR 605], although it provides no guidance in the context of mid-call activation of the service.

6.16.1.1 Feature Interactions

When used in combination with an analogue POTS set, Account Codes will have certain limitations when interacting with other services. For example, the account code service cannot be activated using the flash if other

flash-driven features (such as call waiting or three-way calling) are active. In the case of call waiting, the subscriber is not allowed to use the flash method to enter an account code after the subscriber has already accepted the second incoming call. In the case of three-way calling, the subscriber is not allowed to use the flash method to enter an account code after the subscriber has already initiated the consult leg of the three-way call. Note, though, that an account code can be entered for the second leg if the VSC for the service is dialed prior to dialing the destination digits on the consult leg.