Access tunnels or access conduits were tunnels used for accessing various systems and portions of space-borne stations. Access tunnels are used by the Tyrans and Cardassians. The Federation equivalent of the access tunnel is the Jefferies tube. (DS9: "Behind the Lines")
Appendices
Appearances
Background
The restricted area access tunnel that Rom accesses in "Behind the Lines" has the statement 'A51', which could be an in-joke for Area 51.