Once registered, members initiate ATM withdrawals from within the app and use their phones to scan a QR code displayed on the ATM screen. Successfully scanning the code signals the ATM to dispense the cash.

The absence of a keypad means, Gann pointed out, that no PIN needs protecting, which increases transactions security. The machine's lack of a card reader also makes it invulnerable to skimming.

Devon Watson, vice president of new business at Diebold, said the firm's innovation team developed the ATM in anticipation of future bank and credit union needs.

"Let's face it, the millennial generation is much more comfortable with the use of their phones for all sorts of things and, eventually, the use of mobile wallets in smart phones will be part of their world as well. When that happens, banks and credit unions will need to be ready," he said.

Diebold used a partner in the project, Paydiant, to develop the mobile wallet application which Diebold FCU branded as its own.

Neither Watson nor Gann could provide data on how many users had downloaded the application or used the machine, but Watson said Diebold has collected user surveys.

Beta testers have told Diebold they found it useful to get cash without an ATM card.

"This would make sense; people working in the building might not always take their ATM card with them wherever they went, but they are likely to take their phone," Watson said.

Members also reported the transaction requires less time than card-based ATM transactions.

On the negative side, Watson said some of the members reported they found it difficult to download the application or that they needed assistance registering from within the app.