Tunnel that connects the urban core of the city of Coatzacoalcos, the main industrial port of Mexico, with the industrial district of Allende with its important petrochemical plants. Of its 1,125 m, a total of 696 m are completely submerged at an average depth of 15 m. It has four traffic lanes, two for each direction, and a service gallery for installations and evacuation in case of an alarm. The public address system installed is also a voice alarm system and EN 54 certified, with two COMPACT digital matrices, capacity to control up to 16 speaker zones from the DC-700ETH network control desk and/or from the control computer equipped with the configuration and management software SCM-01. More than 8,000 W power the acoustic projectors and exponential speakers distributed throughout the tunnel.