
You can use transaction FQC0 to maintain posting areas.
You can use transaction FQCR to select account determination data across all posting areas.
The posting area normally consists of different keys. The system first attempts to determine an entry with the key fields that are used. If this does not work, the last key field is excluded at the next attempt. At the last attempt, only the first key field value is used.

General ledger accounts are determined by standard account determination functionality. This function takes a subset of posting parameters and checks allocation tables in FI-CA: posting area S000 and S001.
General ledger account determination is done using main transactions and subtransactions from the line items of postings and additional parameters like company code, division, and account determination ID.
Depending on the industry component used, the account determination ID is derived from either the contract account or from the contract.
You can use posting area S000 and event 1101 to determine the FI-GL receivables account (business partner items).
You can use posting area S001 and event 1100 to determine the FI-GL revenue account (general ledger items).

Each individual posting in the FI-CA subledger is allocated to exactly one receivable or payable account in the general ledger. A negative transfer amount is a credit (payable), and a positive amount is a debit (receivable, usual case).
The FI-GL account in the business partner item of a FI-CA document (receivable) must be designated with the account type X Balance Sheet Account in transaction FS00.
The FI-GL account in the business partner item of a FI-CA document (receivable) must be designated with the reconciliation account category V Contract Account Receivable as well. This prevents unintentional direct postings to these accounts and thus avoids potential complication of the reconciliation process.
The FI-GL account in the general ledger item of a FI-CA document (revenue) must be designated with the account type P Primary Costs or Revenue in transaction FS00.

The receivables account determination requires only the main transaction, which is derived automatically by the system during business transaction processing based on the internal transaction and its allocation to a defined external transaction.
The account determination ID from the contract account enables the derivation of different receivables (and revenues) accounts for different customer groups (private or industry).
The account assignment for main transactions is stored in the posting areas:
- S000 for application area Extended FI-CA
- T000 for application area Telecommunication
- P000 for application area Public Sector
- R000 for application area Utilities
- M000 for application area Media

The revenue account determination also requires the subtransaction. This enables you to allocate different revenue accounts to the same business transaction (main transaction). Furthermore, the tax determination code and the CO account assignment key can be allocated as well.
The account assignment for main and subtransactions is stored in the posting areas:
- S001 for application area Extended FI-CA
- T001 for application area Telecommunication
- P001 for application area Public Sector
- R001 for application area Utilities
- M001 for application area Media
The account assignment for CO objects can be configured by the following steps:
In FI-GL account master data, set the Profit Center field as optional.
In FI-CA customizing, activate the profit center for BP items in the company code settings.
In FI-CA customizing, define the account assignment keys for which you derive CO objects dependent on company code, business area, or segment. Check whether you now need to make the settings for each profit center. This is necessary, for example, if you derive a cost center and a profit center is defined in the cost center. In this case, the profit center in the derived cost center should be the same as the profit center previously copied from a BP item.