Stand-In Processing

Simplify can be configured to support Stand-in processing for timed-out (offline) transactions. A transaction is considered to have timed out when either of the following occurs:

  • The Fusebox response indicates that the Fusebox request to the authorizer timed out.

  • Simplify times out before receiving a Fusebox response.


The Simplify timeout interval for a request to Fusebox is defined individually for each request from the POS in the first 3 bytes of Field 11.

If Stand-in is enabled, a Stand-in Response will be sent for timed-out transactions, allowing these transactions to be approved offline by the POS and resubmitted through Simplify (or directly to Fusebox) for host approval.


Note for purposes of PCI DSS compliance that a Stand-In Response contains encrypted customer data. The merchant is responsible for making this data unrecoverable after completion of the authorization process (PCI DSS 3.0 Requirement 3.2).

For EMV transactions, Simplify can be configured to return EMV tags in the Stand-In Response. The POS can include these tags in the resubmitted transaction. Submitting EMV Stand-In transactions without EMV tags can cause declines from some issuers. See EMV in the Fusebox Integration Guide under “EMV API fields” for more information on EMV tags.

Stand-In support is configured independently for each tender type and applies to the following transaction types:

  • Sale

  • Auth

  • Refund

If Simplify times out waiting for a Host Response to one of these three financial transaction types, the outcome at the POS process will depend on whether Stand-in is enabled, as follows:

  • Stand-in Enabled - The POS process will receive a Stand-in Response (Field 1010 contains “*SLR STAND-IN.”). Simplify will return encrypted transaction data for Stand-In transactions. This will allow the transaction to be resubmitted for host approval. The POS is responsible for approving or declining all Stand-In transactions.
  • Stand-in Not Enabled - The POS process will receive a Host Down Response (Field 1010 contains “*SLR COMMUNICATIONS ERROR.” or *SLR SWITCH TIMEOUT.).

Inquiry processing must be performed at this time as described under Inquiry Message.


Inquiry processing is not affected by whether or not Stand-in is enabled.