The permanent link has been defined in TIA568 B and ISO 11801 AM2, and includes: all the permanently installed horizontal cable, the mated connection at the wiring closet end of the link, the telecommunications outlet at the far end of the link, and an optional transition point (used for example in the case of modular furniture).

The permanent link is used to verify the performance of permanently installed cabling. It differs from the basic link in that it does not include the field tester cord. Of the course, the field tester cord is necessary, but this link definition requires the field tester to somehow compensate for all the characteristics of the cord so that as much as possible the test cord is invisible to the measurement. This is very difficult to do, and to be done properly requires very sophisticated electronics and software in the field tester. The permanent link definition does include the mated plug at the end of the field tester cord, but not the cord itself.