After finding a note from Mies in the safe in FunFrock's headquarters, Twinsen heads to Mies' house and talks with him. Mies tells Twinsen to pick the pass from his desk, which grants him acces to the teleportation center.
"M. Mies van der Rooh's pass. This pass will grant you access to the Teleportation Center. You will still have to use Gawley's Horn on the left, after the first guard post."