Offline transaction v/s Online transaction
Offline transaction v/s Online transaction
Difference between Offline Payment transaction and Online payment transaction?
Offline Payment transaction: The decision of the transaction is taken by the combination of Card (Payment Card) and Terminal (POS machine). In EMV terminology the transaction is completed (approved/declined) at First Generate AC command.
Online Payment Transaction: The decision of the transaction is taken the issuer. This scenario occurs when the Terminal is
- Card requested to go Online.
- Terminal decides to go online if the value of certain Accumulators and counter exceeds a pre-defined (during personalization) limit.
In this case Second Generate AC command is issued the POS to retrieve some more information to be sent to the Issuer. With the help of this additional data (This additional data varies based on the whether the transaction is a DDA/CDA transaction), Issuer (Bank which issued the card) shall either approve/decline a transaction.
Referring to Section 10.2 and 10.9 of EMV book 2 would help to understand more. Link below.
https://www.emvco.com/wp-content/uploads/2017/05/EMV_v4.3_Book_3_Application_Specification_20120607062110791.pdf
Please note that the decision to go online is also based on the IAC online tag in the card side and the TAC ONLINE tag in the terminal side.
These 5 bytes tags are checked against the TVR (5 bytes). if at least one bit match, the decison is to go online.
Thanks for your explanation. it’s very useful to understand the topic.