An Intermediate Distribution Frame (IDF) is a free-standing or wall mounted rack for wiring or cable from a Main Distribution Frame (MDF) - also called the Combined Distribution Frame (CDF) - and leading to individual cables for each piece of equipment such as workstations, personal computers and other end-user devices.
IDFs are used for Wide Area Networks (WANs), Local Area Networks (LANs), customer/end-user buildings and telephone exchange central offices.
An Intermediate Distribution Frame for telephone exchange offices may also contain termination equipment for a variety of components. For LANs and WANs, IDFs may also contain: Components for backup systems such as hard drives, RAID arrays, CD-ROM drives, hubs, routers & switches for networking, and connections for fiber optic, coaxial and other cables.
An MDF may enter the first floor of a building from a phone company or other buildings then the IDF would run through the walls to each successive floor where connections for lines to individual workstations, personal computers, etc. are located.
Contractors are cautioned not to use the IDF rack for grounding other equipment, such as welding or test equipment. Possible voltage and current spikes may easily damage sensitive electronic equipment as the IDF may not have sufficient grounding to convey excess voltages to earth.