The SuperLooper ISDN (PRI) Loopback Jack and Plug can be used to check ISDN (PRI) cabling for broken or shorted wires and network interfaces for the simplest functionality. When installing primary network backbone circuits, the simple check of an ISDN (PRI) interface or jumper cable using the SuperLooper ISDN (PRI) Loopback Jack and Plug can save hours of infrastructure downtime. The SuperLooper ISDN (PRI) Loopback Jack and Plug can be plugged directly into the network interface port or onto the cable to be tested.