CAT 3 Keystone Inserts
Keystone modules, also called inserts, are rectangular-faced, 14.5 mm x 16.0 mm packages for low-voltage electrical, telecommunication, audio, video and optical connections. These plastic, standardized packages snap into wall plates, patch panels and surface-mount boxes via a flexible tab along their upper surface making for a fast and easy installation. There are two basic varieties of keystone connections. The first employs duplicate female jacks on its front and back to serve as a mounted, pass-through coupler. The second type uses a female jack on its face connected to hard-wired, crimp or solder connection for use with wall-installed bulk cable runs.
Because keystones are replaceable, interchangeable and relatively inexpensive, they are ideal for custom installations that might require future modification. In fact, the list of available keystone type inserts is rather extensive and includes a variety of network, fiber optic, audio, video and A/V options.