establishment, which allows for the use of a scrip cash dispenser. ATMs typically connect directly to their host or ATM Controller on either ADSL or dial-up modem over a telephone line or directly on a leased line. Leased lines are preferable to plain old telephone service (POTS) lines because they require less time to establish a connection. Less-trafficked machines will usually rely on a dial-up modem on a POTS line rather than using a leased line, since a leased line may be comparatively more expensive to operate compared to a POTS line. That dilemma may be solved as high-speed Internet VPN connections become more ubiquitous. Common lower-level layer communication protocols used by ATMs to communicate back to the bank include SNA over SDLC, TC500 over Async, X.25, and TCP/IP over Ethernet. In addition to methods employed for transaction security and secrecy, all communications traffic between the ATM and the Transaction Processor may also be encrypted using methods such as SSL. 2021 Global use There are no hard international or government-compiled numbers totaling the complete number of ATMs in use worldwide. Estimates developed by ATMIA place the number of ATMs currently in use at 3 million units, or approximately 1 ATM per 3,000 people in the world. To simplify the analysis of ATM usage around the world, financial institutions generally divide the world into seven regions, based on the penetration rates, usage statistics, and features deployed. Four regions (USA, Canada, Europe, and Japan) have high numbers of ATMs per million people. Despite the large number of ATMs, there is additional demand for machines in the Asia/Pacific area as well as in Latin America. Macau may have the highest density of ATMs at 254 ATMs per 100,000 adults. ATMs have yet to reach high numbers in the Near East and Africa. Hardware An ATM is typically made up of the following devices: CPU (to control the user interface and transaction devices) Magnetic or chip card reader (to identify the customer) a PIN pad for accepting and encrypting personal identification number EPP4 (similar in layout to a touch tone or calculator keypad), manufactured as part of a secure enclosure Secure cryptoprocessor, generally within a secure enclosure Display (used by the customer for performing the transaction) Function key buttons (usually close to the display) or a touchscreen (used to select the various aspects of the transaction) Record printer (to provide the customer with a