I WAS JUST WONDERING ABOUT ATM MACHINES AND COULD NOT GET WHAT THEY ARE ACTUALLY DOING .
I HAVE AN ACCOUNT IN A BANK A(SAY) AND ONE IN B I GO TO AN ATM OF BANK A AND
GET 2000 INDIAN RUPEES OUT(INITIAL BALANCE WAS 20000) NOW I GET MY BIKE AND GO TO ANATHER ATM INSERT MY CARD AND WHEN I CHECK BALANCE IT WAS 18000 RS (THAT IS 20000-20000=18000).
HOW DO ATM KNOW THAT I HAVE WITHDRAWN 2000 RS 30 MINUTES AGO?
THE MOST PROBABLE ANSWER IS THEY HAVE NETWORKING OF SOME KIND BETWEEN ATM'S OF BANK A.

NOW AT THIS POINT I HAVE 18000RS IN MY ACCOUNT I GO TO BANK B WHICH IS A BANK WHO ACCEPT CARDS OF BOTH A AND B BANK'S.I AGAIN INSERT ATM CARD OF BANK A AND CHECK MY BALANCE IT IS 18000----------------

WHAT IS GOING ON HERE.
IF IT IS SOME KIND OF NETWORKING THAN IT MUST BE SOMETHING LIKE WIRELESS NETWORKING BECAUSE I CAN NOW SEE A MOBILE ATM MACHINE ON INDIAN ROAD'S.

IF ANYONE CAN GIVE ME SOME LINK ON THIS TOPIC I WILL BE THANKFUL .