Telecommunications Rooms, Enclosures, and Equipment Rooms

The telecommunications room or enclosure is where your network devices are aggregated into switches. These switches route the signals from these devices to the equipment room where servers and storage equipment are located. In this section, we'll cover the function of these rooms, along with suggested design elements. From there, we'll discuss the pieces of equipment found within a typical telecommunications and equipment room. We'll conclude with a brief discussion on network devices.

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Cabling @ Work: A Telecommunications Room by Any Other Name

Telecommunications rooms or enclosures are known by a number of names and acronyms. Although some cabling professionals use the term wiring closets, others call themintermediate cross-connects (ICCs) or intermediate distribution frames (IDFs). The ANSI/TIA-568-C.1 standard refers to them as telecommunications rooms. They are usually remote locations in a large or multistory building.

The telecommunications rooms or enclosures are all connected to a central wiring center known by the ANSI/TIA-568-C.1 standard as an equipment room. Other cabling professionals call this the main distribution frame (MDF) or the main cross-connect (MCC).

The terms intermediate cross-connect, main distribution frame, and main cross-connect are incomplete descriptions of the rooms' purposes because modern systems need to house electronic gear in addition to the cross-connect frames, main or intermediate.

Horizontal cabling is run from telecommunications rooms to the workstation areas. Backbone cabling runs from the telecommunications rooms to the equipment rooms and between telecommunications rooms.

Typically a telecommunications room is a closed space; however, the ANSI/TIA-568-C.1 standard allows for workspace equipment to be connected to telecommunications enclosures. Telecommunications enclosures are typically located in open areas of an office building closer to the workspace than a telecommunications room. These enclosures contain mini-switches and patch panels and are small enough in size to be placed above the ceiling of the workspace area or on walls. These telecommunications enclosures have the same functionality as the telecommunications room, but since they are smaller in size and more efficient, using them allows for less expensive network designs. (For more information, visit TIA's Fiber Optics LAN Section at www.fols.org.)

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Three types of wiring locations exist: telecommunications rooms, telecommunications enclosures, and equipment rooms.

Depending on the size of your organization and the size of your building, you may have one or more telecommunications rooms connecting into an equipment room. Telecommunications rooms are strategically placed throughout a building to provide a single point for termination from your work areas. In a multistory building, you should have at least one telecommunications room per floor. As the distances between your end devices and telecommunications room approach their recommended maximum limits (90 meters), you should consider implementing additional telecommunications rooms. Ideally, these are included during the planning stage prior to construction or remodeling.

Telecommunications rooms are connected to the equipment room in a star configuration by either fiber or copper backbone cables. As we mentioned in our discussion of backbone cabling, fiber is preferred because fiber allows for distances from the equipment room to the last telecommunications room of up to 2,000 meters for multimode and 3,000 meters for single mode. When connecting with UTP copper, the backbone run lengths must total no more than 800 meters for telephone systems and no more than 90 meters for data systems.

A telecommunications enclosure is essentially a mini-telecommunications room. These enclosures contain active switches and patch panels and have the same functionality as the equipment located in a telecommunications room. The advantage of using telecommunications enclosures instead of telecommunications rooms is in the higher switch port utilization and cost savings obtained from eliminating the construction of dedicated rooms and associated HVAC loading. The Fiber Optics LAN Section of TIA (www.fols.org) has conducted extensive cost modeling showing the advantages of using telecommunications enclosures. However, telecommunications enclosures do not come without disadvantages, such as the need to service certain types of telecommunications enclosures in an open workspace.