The CMS electromagnetic calorimeter will provide excellent performance (in energy and position measurements) in a very hostile environnment (radiation beam crossing rates). It consists of a barrel made of 61200 lead tungstate crystals each read out by two avalanche photodiodes and of two end caps with 14488 crystals read out by vacuum phototriodes. In early 2002, the front-end electronics was redesigned and is now base on trigger towers that calculate the trigger primitives on detector at each bunch crossing and transmit raw data upon level-1 trigger acceptance. The status of the calorimeter construction is presented, as well as results of beam tests performed in 2003 using the new electronics scheme which confirm that the design performance can be reached.