All of ALMA's telescopes must talk to one computer system. That is how they work together as an array. Depending on where a telescope may be placed that day, miles of fiber optic and power cable may be required to reach the telescopes from the AOS Technical Building.
At places, the cables cross the dirt roads that the Transporters use to carry telescopes around the site. Concrete trenches protect these glass fibers from several hundred tons of laden Transporter.