Congressional votes are calculated either by an electronic voting system or by voice vote. These votes are called Yea/Nay votes. The electronic system also registers each voting member's individual response to the bill, while the voice vote does not.
Both voice and electronic votes are compiled and put into a public record on the U.S. Senate, House and Congress websites. Each record states the method by which the votes were collected and which individual collected the result. The House votes are collected by the House tally clerks, who are overseen by the Clerk of the House. The Senate votes are collected by the Senate bill clerk who is overseen by the Secretary of the Senate.
According to the Federation of American Scientists, the electronic voting system was used for the first time on Jan. 23, 1973. The idea for an automated system to record votes was proposed 87 years earlier. Thomas Edison invented the first electronic vote recorder in 1869, which was not used by Congress. It was not until 1970, with the passing of The Legislative Reorganization Act, that Congress began to develop and install the electronic voting system. The system's first use on was for a quorum call.