Physical labels for cabling/components help you navigate complex structured cabling systems.

Don't underestimate the importance of labels! Much like the signs required to mark local streets and super highways, physical labels for cabling and components are necessary when it comes to navigating complex structured cabling systems. Even the simplest of these systems will typically contain hundreds or thousands of discrete components, which, over time, come into and out of service repeatedly. The ability to locate, isolate, and manage required components will depend heavily on whether a clear, reliable labeling scheme is in place.

There are two general techniques to choose from for labeling physical wiring and related hardware. The first is to devise a sequential alphanumeric scheme that results in each component's having its own unique ID.

The second scheme builds on the first by incorporating a degree of intelligence within the semantics of the naming scheme (sometimes referred to as intelligent naming or intelligent labeling). Intelligent labeling schemes not only provide unique identifiers for all cabling components, but can also convey information, such as where cables terminate, or where in a wiring closet the other end of a workstation jack can be found. The most successful approach involves the use of an intelligent labeling scheme for all structured cabling systems.

Labeling communications outlets Individually label each position within each outlet assembly (i.e., each jack or transmit/receive fiber pair) with a unique three-syllable identifier also unique to each building domain. You may apply this label to the faceplate of outlet assembly or in some other way that clearly ties the label to the named position.

Fig. 1 shows how to label individual jacks in an outlet assembly. Each of the jacks shown clearly displays the three-syllable scheme just mentioned. An example of this scheme is "1A-WA-01." In this example, the first syllable, "1A," designates the source of the wiring tied to the named jack. In this case, the source is Wiring Closet 1A. The number "1" refers to the first floor, and "A" refers to Intermediate Distribution Frame (IDF) A on that floor.

The second syllable, "WA," refers to the field (i.e., each common group of connecting hardware) in Wiring Closet 1A, in which the cable tied to the named jack terminates. A field, in this context, refers to both a physical grouping and logical grouping of common connecting hardware in a wiring closet or equipment room, which are segregated in such a way as to be distinct from every other field. In most cases, termination fields in wiring closets will either be wall or rack mounted. In the example, the "W" indicates a wall-mounted field, and the "A" indicates Field A specifically.

The third syllable, 01, is used to identify the position within the named field (i.e., the "WA" field, in this example) that corresponds, specifically, to the named jack at the workstation. You can think of this position as the other end of the circuit in horizontal station wiring. It will physically consist of a jack, or a group of IDC-type connectors on connecting hardware, depending on the type of connecting hardware used. Each RJ-45 in Rack Fields "A" and "B" is a position that corresponds to a jack at a workstation.

Use legible, preferably preprinted labels of a permanent or lasting nature on all faceplates. Handwritten markings should be unacceptable.

Connecting hardware labeling. Three kinds of connecting hardware are typically used for communications wiring: IDC-type connecting blocks for voice-related UTP wiring; IDC-type jack panels for data-related UTP wiring; and ST or compatible type patch panels for fiber-optic (FO) wiring. In spite of the physical and technical differences between these three equipment types and the media they support, all three share one thing: They terminate their respective media onto discrete positions within each hardware type, which, in turn, are physically grouped together to form fields.

For voice-related UTP riser cables, treat each individual pair as a separately labeled channel, with the resulting two conductors associated with each pair labeled as a separate position on the connecting hardware.

For data-related horizontal and UTP in-building backbone cables (i.e., when you use patch panels to terminate UTP cables), consider and label each RJ-45 type jack in every patch panel as a separate position. In this case, each data-related RJ-45 will be composed of four twisted pairs.

For FO cables, each pair of fiber strands terminated onto a corresponding pair of ST or compatible type connectors should be treated, and labeled, as a separate position. Again, a position represents the smallest communications channel intended for discrete usage.

Group all connecting hardware into separate logical fields within each wiring closet or equipment room. Accordingly, number each position sequentially within each such field. A two-, three-, or four-digit sequential number of your choosing should be sufficient. Also clearly label each field of connecting hardware within each closet or equipment room.

Other important fields will contain equipment required for local area networks (LANs), such as hubs or wiring concentrators. Positions, in the case of these equipment fields, will equate to ports. Label these separately as discussed below.

Cable labeling Label all cables used in a structured cabling system. As in the case of communications outlets, the labeling scheme for cables should call for the use of a unique, three-syllable identifier for each cable. However, you must handle each of the three cable types in a slightly different manner.

Tag each 4-pair cable installed in horizontal station runs with labels along its length at intervals of between 10 ft and 15 ft. Label all such cables clearly and visibly at each end. The labeling scheme used should consist of a three-syllable identification that is unique to each cable in each building domain. Fig. 1 uses the following example for one of the cables shown: 1A-RA-01.

The first syllable, "1A," indicates the named cable originates from Wiring Closet 1A, which is the A wiring closet on the first floor. The second syllable, "RA," indicates the named cable terminates in the rack-mounted Field A of that IDF; and the third syllable, "01," specifies the position occupied by the named cable in Field RA.

As you can see, the labeling scheme for cables in horizontal runs is identical in content to the labels used for corresponding outlet assemblies. Each 4-pair cable should bear the same unique identifier as the jack or fiber pair of connectors to which it attaches at the workstation.

In general, cables installed inside buildings for backbone or riser applications will connect wiring closets to one another or to equipment rooms that are centrally located. Individually tag these cables with labels along their lengths at intervals of between 10 ft and 15 ft; they should be clearly labeled at a convenient location within sight of each end. The labeling scheme used should consist of a three-syllable identification that is unique to each cable in each building domain.

Fig. 2 (on page 32F) shows two types of in-building backbone cables run between Wiring Closet (IDF) 1A and Equipment Room (MDF) 00. The first type consists of copper UTP; the second is FO cable.

One of the copper UTP cables reads "00-1A-C1." The first syllable, "00," indicates that the location of one end of the cable is in MDF (Equipment Room) 00. The second syllable, "1A," indicates that the other end of the cable is in IDF (Wiring Closet) 1A. The third syllable, "C1," indicates that the named cable is made up of copper media and is the first such copper cable between the two points named in the first two syllables. Accordingly, the third syllable for the second and third copper cables shown in Fig. 2 are "C2" and "C3" respectively.

The FO cables follow the same fashion as the copper UTP cables, except for the third syllable. In this case, the prefix to the third syllable changes from "C," for copper, to "F," for fiber. The numerical suffix then progresses from 1 to 3, resulting in third syllables "F1," "F2," and "F3" respectively.

In general, cables installed between buildings across campuses will connect IDFs (wiring closets) or MDFs (equipment rooms) in one building to those in others. All such cables should be individually tagged with labels along their lengths at intervals of between 50 ft and 100 ft when possible, or wherever jacketing material is exposed in outside plant conditions (e.g., aerial cables, manholes). You should also clearly label them at a convenient location within sight of each end.