Monetary Assets vs Non-Monetary Assets

In the Oracle General Ledger User Guide, it mentioned about the rates used for Translation between Monetary Assets, Liabilities and Non-Monetary Assets, Liabilities. My question is how does the system knows which account is Monetary Asset and Liabilities and which account is Non-Monetary Assets? When we define an account code, we only state whether the account is a revenue or asset or liability or expense, etc... where do we indicate whether it is Monetary or Non-monetary?

Thanks in advance...