Oct. 6 (Bloomberg) -- Mexico’s lower house of Congress approved legislation forcing telecommunication carriers to let customers pay for calls per second instead of rounding to the nearest minute.

With 327 votes in favor, none against and one abstention, lawmakers amended a bill to require carriers to offer calls billed by the second. The per-second rates must be competitive with plans that offer packages of minutes at a flat rate, according to the legislation.

Mexican lawmakers and regulators are putting pressure on wireless carriers to reduce prices for consumers. Earlier this year, the nation’s Federal Telecommunications Commission forced America Movil SAB and Telefonica SA, the nation’s largest mobile-phone carriers, to cut rates charged to connect calls from other carriers.

America Movil, the Mexico City-based company controlled by billionaire Carlos Slim, has about 70 percent of Mexico’s wireless subscribers. Madrid-based Telefonica has 22 percent.

To become law, the bill must also be approved by the Senate and would require President Felipe Calderon’s signature.

--Editors: Donna Alvarado, Niamh Ring

To contact the reporters on this story: Adriana Lopez Caraveo in Mexico City at adrianalopez@bloomberg.net; Crayton Harrison in Mexico City at tharrison5@bloomberg.net

To contact the editor responsible for this story: Peter Elstrom at pelstrom@bloomberg.net