Modular RJ-45 Jack for digital business phones and Ethernet application. The Radio Shack 8-Pin Surface-Mount Modular Jack lets you install a jack for digital business phones or Ethernet applications in any location. The block's eight slotted screw terminals let your configure it as an RJ-45 modular jack for 6-wie (ISDN) or 8-Wire (Ethernet 10-Base T) cable.