New Delhi, March 5 (IANS): The Election Commission has ordered 20,000 voter verifiable paper audit trail (VVPAT) systems, Chief Election Commissioner V.S. Sampath said Wednesday.

"The paper trail system was experimented with in two assembly constituencies in Nagaland and Mizoram. Induced by experimentation, we have ordered for the supply of 20,000 such machines," Sampath said at a press conference at which he announced the schedule for the Lok Sabha elections.

"We are waiting for the machines. As soon as they are received, we will use them in as many constituencies as possible," he said.

The commission is likely to receive these new systems by March 31.

Under this system, when a voter presses a button on the electronic voting machine to select the candidate he wants to vote for, a slip of paper bearing the name and symbol of the party will briefly appear for about 10 seconds, after which it will fall into a secure box, thus maintaining a paper trail of all the votes cast.

At present, there are 600 units with the Election Commission.