Definition - What does Keystone Jack mean?
Keystone jacks are keystone module connectors used in data communication and LAN wiring. It is the female connector that is usually mounted in a wall plate or patch panel and is connected to the matching male connector, called the keystone plug. A keystone module is a snap-in package that is used for mounting various types of low-voltage electrical jacks. It can also be used for mounting optical connectors into the wall plate or patch panel.
Techopedia explains Keystone Jack
Keystone jacks are used in the wiring system of LAN and Ethernet connections. They are called keystone jacks because the jack looks similar to an architectural keystone, just like the standard RJ-11 wall jack that is used to connect telephones, fax machines and dial-up systems.
They offer the advantage of providing versatility. A single panel can be used to mount many types of keystone jacks in either shielded or unshielded forms. They are also capable of accommodating different types of cords or cables and various types and numbers of conductors. Shielded keystone jacks help protect data from electromagnetic interference.
Some keystone modules have a jack on the front with a different mechanism for the back end. Other modules may have a jack on both the front and the back side. Wiring a keystone jack can be done by punching down the wires into the blades built into the keystone jack.