Automatic Teller Machines (ATMs)
ATM innovation paralleled the growth of the PC and telecommunications industries.Earlier ATM's operated in the operated in a local mode. Here, transaction authorization took place based on the information recorded in the magnetic bands
of the cards. Then they were connected to the bankâ„¢s centralized systems. the ATM would work on-line but in the event of communication loss it had the
ability to authorize the transaction with the information recorded on the magnetic band.Then ATMs started to work exclusively on-line. if the ATM loss
communication with its central system, there would not be any service. algorithms that allowed for the encryption of the information were utilized; the most commonly utilized algorithm is DES (Delta Encryption Standard).
ATM Hardware and Software Characteristics
the first categorisation is based on its PC architecture the second classification based on ATM specific functions such as card reading, cash dispensing,
cash storage, user and operatorâ„¢s video and keyboard interaction, etc.Most ATM's have an operating system (OS/2, or Windows based).services based on the TCP/IP protocols are provided. The application softwaremaybe supplied by the manufacturer of the ATM machine.
The ATM card transaction consists of the following steps:
a)Insert card and PIN number
b)Select transaction type and amount
c)Information sent to central system
d)Central system validates information
e)Authorization sent to ATM
f)Cash and receipt provided to user
The user accesses the ATM through the magnetic band card supplied by the bank. the application requests the userâ„¢s PIN and the
type of transaction to be conducted, after the card is validated by the ATM. control data is added to create a requirements message to the
authorizing system. This message, a Transaction Request or TREQ, is sent through data communications network. The authorizing system receives the TREQ and starts to decode and process the
informationand the Transaction Reply, or TREPLY,is sent back to the inquiring ATM. Upon TREPLY reception, the ATM decodes and processes the information and
presents the transaction results to the user.a Transaction Confirmation or, TCONFIRM, to the
authorizing system about the final result of the transaction.