This document discusses the trading mechanism of stock exchanges in India. It explains how the traditional open-outcry system was replaced by screen-based trading systems like NSE's NEAT and BSE's BOLT to provide more efficiency, liquidity, and transparency. It outlines the various types of orders that can be placed, such as buy/sell, price-based, and time-based orders. It then describes the six main steps involved in trading stocks on the exchange: finding a broker, opening an account, placing an order, order execution, contract note preparation, and contract settlement. Finally, it provides details on how online trading works through a network of computers and satellites.