Software Design

ATM Cash Withdrawal Transaction Machine

State Diagrams · made in Skemio

State diagram of ATM cash withdrawal: CardInserted, PinValidated, Authorizing, CardEjected, Dispensing, and Terminal states.
State diagram of ATM cash withdrawal: CardInserted, PinValidated, Authorizing, CardEjected, Dispensing, and Terminal states.
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What it shows

  • Card authentication must precede PIN verification and account lookup.
  • Cash dispensing requires a two-phase commit before ledger debiting.
  • Ejecting the card before dispensing cash prevents customers leaving cards.

The takeaway

Critical financial terminals order state transitions to ensure hardware actions match ledger balances.

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