Automated Teller Machine (ATM) – It is an electronic machine which is operated by customers and allows performing for financial transactions such as transfer funds, cash withdrawals, and deposits. It also used for obtaining account information at any time and without the help of bank staff. The ATMs in banks are installed at easily approachable locations or near the main gate of bank. The facility of ATM provides 24 hours customer service and dispenses currency note of specified values only. John Shepherd-Barron invented the automatic teller machine in 1960.

General working of ATM – First of all a card is issued to the customer by the bank which bears his/her name and Personal Identification Number (PIN). This card is called as ATM card. ATM is magnetically coded and can be read through card reader inside the machine. First of all a person inserts the card in the ATM machine at a particular slot provided for this purpose. The machine reads the card and after it is recognized, the person enters his personal identification number (PIN). When identity of customer is established, the ATM machine allows the customer to enter the amount to be withdrawn. After different checks and processes, cash is made available to the customer at output slot of ATM. After completion of transaction the card is automatically ejected.

The automated teller machine has two input devices and four output devices such as

Input Devices:

1. Card reader
2. Keypad

Output devices

1. Display Screen
2. Speaker
3. Cash dispenser
4. Receipt Printer

The working of input devices and output devices discuss in detail

Input devices

1. Card reader – It is an input device which reads data from an ATM card. When the card is swiped on the card reader which reads the data from the card is passed on the server. After that the server gets the information by using the card swiped by the customers.                                                                                                                
2. Keypad – When the card is recognized by the ATM machine then enters the personal identification number of card and also asks for withdrawal and balance enquiry with the help of keyboard. Each card has an unique PIN number and sent in encrypted form. The key board which is linked with ATM machine has 48 keys and is interfaced to the processors.                                                                                        

Output devices

1. Display screen – The display of ATM machine shows the information of transaction by the user. All the steps of withdrawal is shown in the display screen. A LCD or CRT screen is mostly used by ATMs.                                                            
2. Speaker – The speaker provides information about transaction in audio form when the key is pressed.
3. Cash dispenser – It is the main part of the ATM machine where the money is received and collected by the customer. The working of this section is to count and provide the money to the user.                                                                                            
4. Receipt printer – The function of the receipt printer is to provide details of your withdrawal amount, balance in account, date and time of the withdrawal of money.                                                                                                                                                   

ATM Networking – The internet service provider (ISP) make contact between host processors and ATM. When the process of transaction occur, the information provided by the user. The ATM machine passed the information to the host processor. The host processor checks the details of the user with recognized bank. If the details are same, the approval code sends by the host processor to the ATM machine hence the cash can be transferred to the customer.