Sequence Charts Automatic Teller Machine. Automatic teller machines (ATM) usually services credit and cash cards of a consortium of financial institutions (Diners, Mastercard, Visa, etc., as well as Citibank (New York, NY, USA), HSBC (Hong Kong and Shanghai Bank Corporation, London, UK), etc.). So you may think of four sets of "players": You, the card holders, the ATMs, the consortia, and the specific financial institutions of the consortia. A particular ATM is bound to a specific set of card types, one consortium, and a specific set of financial institutions. An ATM usually offers a number of services: cash withdrawal, cash deposit, cash transfer, inquiry about account status, etc. An example protocol for the opening of a card transaction using an ATM is as follows: user inserts card into the ATM; the ATM requests card password from the user; the user keys password into the ATM; the ATM requests verification from the consortium; the consortium requests verification from the financial institution of the card; the financial institution either OKs or does not OK the transaction and so informs the consortium; the consortium passes the verification response back to the ATM; and the ATM passes it back to the user. If response was OK, the user may continue. Exercise 13.1.1: Develop an appropriate MSC for a quadruplet of User, ATM, Consortium and Financial Institution instances.

Exercise 13.1.2: Develop a possible MSC, following a successful, i.e., OK'ed verification opening, for a cash withdrawal transaction.

Exercise 13.1.3: Develop a possible MSC, following a successful, i.e., OK'ed verification opening, for a cash transfer transaction. You are to fill in all relevant details left out above and to take into account that the user makes mistakes.