On the RER, there are 2 types of indicators used, the first generation model which only indicates the termini of trains stopping at a station through the use of square lights located beside the words bearing the name of a terminus, and the second generation model which includes an LED display above the square lights indicating the terminus and train service. These displays are only used on the RER line A, RER line B and at Gare de Châtelet – Les Halles station on RER line D, and can be inaccurate at times due to the lack of communication between SNCF and RATP, the two operators of the RER.