Both types of action code take the values Denial, Online, and Default. Each action code contains a series of bits which correspond to the bits in the Terminal verification results (TVR), and are used in the terminal's decision whether to accept, decline or go on-line for a payment transaction. The TAC is set by the card acquirer; in practice card schemes advise the TAC settings that should be used for a particular terminal type depending on its capabilities. The IAC is set by the card issuer; some card issuers may decide that expired cards should be rejected, by setting the appropriate bit in the Denial IAC. Other issuers may want the transaction to proceed on-line so that they can in some cases allow these transactions to be carried out.