Open item processing allows you to allocate (match / link) each debit transaction to a credit transaction and each credit transaction to a debit transaction; which are posted to the same account. 

Basically most or all receipts or payments transactions, should be matched when processing transactions in batches. When allocating transactions to an account, which is set as an Open item account, an "Open item selection" screen will list all the transactions with outstanding amounts. You may then select a specific outstanding transaction on a list to link the transaction to. 

By default, Open item is not activated when an account is created. You need to activate or set an account as an Open item account.

Debtor (customer / client) accounts / Creditor (supplier / vendor) accounts

The basics for debtor (customer / client) accounts and creditor (supplier / vendor) accounts, which is set as an "Open item account", is as follows:

• Debtor (customer / client) accounts - By default, the "Open item selection" screen will be launched when allocating credit transactions (e.g. payments received or credit notes, etc.) to debit transactions (e.g. Invoices, Credit notes, and other debit transactions such as interest on overdue accounts, etc.)   
• Creditor (supplier / vendor) accounts - By default, the "Open item selection" screen will be launched when allocating debit transactions (e.g. payments on account or supplier returns, etc.) to credit transactions (e.g. Purchases, and other debit transactions such as charge amounts, etc.).    

There are various options to filter and manage the details, totals and transactions of open item accounts. 

Ledger accounts 

The "Open item link" for a specific ledger account may be opened with a double-click from the Totals tab or the Transactions tab on Open item link.

Some examples of such ledger accounts may be;

• Advance accounts - You may wish to keep track and manage advances paid to an employee or salesperson for subsistence and travel. After the employee or salesperson returns from his trip, he return the expenses source documents and refund any unused monies. When processing these source documents in batches, etc., these transactions may be linked (matched) to the original advance.  
• Suspense / Clearing accounts - When an transactions needs to be managed, matched or reconciled, etc.

Open item link access 

To access the Open item link feature, click on the Open item link icon (Default ribbon).

There are four (4) tabs, i.e.  Totals, Transactions, Unposted batches and Due tabs to manage open item accounts.

You may also edit or unlink the existing links, or even convert a specific account to the “Balance brought forward” method, where any payment or receipt will be set off against the oldest outstanding amount.