Monday, February 27, 2012

Wall Plate Jack Considerations | Modular Wall Plates

Modular wall plates are the most common type of wall plate in use for data cabling because they meet the various ANSI/TIA and NEC standards and codes for quality data communications cabling. So modular wall plates have the widest variety of jack types available. All the jacks available today differ based on a few parameters, including the following:
  • Wall plate system type
  • Cable connection
  • Jack orientation
  • ANSI/TIA-568-C.2 and -C.3 wiring pattern

Wall Plate System Type

Remember how the type of wall plate you use dictates the type of jacks for that wall plate? Well, logically, the reverse is also true. The interlocking system that holds the jack in place in the wall plate differs from brand to brand. So, when you pick a certain brand and manufacturer for a jack, you must use the same brand and manufacturer of wall plate.

Cable Connection

Jacks for modern communication applications use insulation displacement connectors (IDCs), which have small metal teeth or pins in the connector that press into the individual wires of a UTP cable (or the wires are pressed into the teeth). The teeth puncture the outer insulation of the individual wires and make contact with the conductor inside, thus making a connection. This process (known as crimping or punching down, depending on the method or tool used) is illustrated in Figure 1.

Figure 1: Using insulation displacement connectors (IDCs)
Though they may differ in methods, any connector that uses some piece of metal to puncture through the insulation of a strand of copper cable is an IDC connector.

Jack Orientation

Yes, jack orientation. The individual wall plate systems use many different types of jacks, and some of those systems use jacks with positions other than straight ahead (which is the "standard" configuration). These days, a popular configuration is a jack that's angled approximately 45 degrees down. There are many reasons that this jack became popular. Because it's angled, the cable-connect takes up less room (which is nice when a desk is pushed up tight against the wall plate). The angled connector works well in installations with high dust content because it's harder for dust to rest inside the connector. It is especially beneficial in fiber-to-the-desktop applications because it avoids damage to the fiber-optic patch cord by greatly reducing the bend radius of the cable when the cable is plugged in. Figure 2 shows an example of an angled connector.

Figure 2: A faceplate with angled RJ-45 and coaxial connectors
Angled connectors are found in many different types of cabling installations, including ScTP, UTP, and fiber optic.

Wiring Pattern

When connecting copper RJ-45 jacks for universal applications (according to the standard, of course), you must wire all jacks and patch points according to either the T568-A or T568-B pattern. Figure 3 shows one side of a common snap-in jack to illustrate that the same jack can be terminated with either T568-A or T568-B color coding. (You may want to see the color version of this figure in the color section.) By comparing Table 1 and 2, you can see that the wiring schemes are different only in that the positions of pair 2 (white/orange) and pair 3 (white/green) are switched. If your company has a standard wiring pattern and you wire a single jack with the opposing standard, that particular jack will not be able to communicate with the rest of the network.

Figure 3: A common snap-in jack showing both T568-A and T568-B wiring schemes
Table 1 shows the wiring color scheme for the T568-A pattern. Notice how the wires are paired and which color goes to which pin. Table 2 shows the same for T568-B.
Table 1: Wiring Scheme for T568-A 
Pin Number
Wire Color
Table 9.3: Wiring Scheme for T568-B 
Pin Number
Wire Color

Friday, February 24, 2012

Number of Jacks | Modular Wall Plates

The first decision you must make when using modular wall plates is how many jacks you want in each wall plate. Each opening in the wall plate can hold a different type of jack for a different type of cable media, if necessary. Additionally, each jack must be served by its own cable, and at least one of those should be a four-pair, 100 ohm, UTP cable.
The number of jacks a plate can have is based on the size of the plate. Fixed-design wall plates mainly come in one size. Modular plates come in a couple of different sizes. The smallest size is single-gang, which measures 4.5 high and 2.75 wide. The next largest size is called double-gang, which measures 4.5 by 4.5 (the same height as single-gang plates but almost twice as wide). There are also triple- and quad-gang plates, but they are not used as often as single- and double-gang plates. Figure 1 shows the difference between a single- and double-gang wall plate.

Figure 1: Single- and double-gang wall plates
Each manufacturer has different guidelines about how many openings for jacks fit into each type of wall plate. Most manufacturers, however, agree that six jacks are the most you can fit into a single-gang wall plate.
With the advent of technology and applications such as videoconferencing and fiber-to-the-desktop, users need more jacks and different types of cabling brought to the desktop. You can bring Category 3, Category 5e, or Category 6 UTP cable, fiber-optic and coaxial cable all to the desktop for voice, data, and video with 6-, 12- and 16-jack wall plates.

Tuesday, February 21, 2012

Fixed-Design Wall Plates

A fixed-design wall plate cannot have its jack configuration changed. In this type of wall plate, the jack configuration is determined at the factory, and the jacks are molded as part of the plate assembly.
You must understand a few issues before choosing a particular fixed-design wall plate for your cabling installation, including the following:
  • Number of jacks
  • Types of jacks
  • Labeling

Number of Jacks

Because fixed-design wall plates have their jacks molded into the faceplate assembly, the number of jacks that can fit into the faceplate is limited. It is very unusual to find a fixed-design faceplate with more than two jacks (they are usually in an over-under configuration, with one jack above the other). Most fixed-design wall plates are for UTP or coaxial copper cable only; but fiber-optic fixed-design wall plates are available for fiber-to-the-desk applications. Figure 1 shows some examples of fixed-design wall plates with various numbers and types of sockets.
Figure 1: Fixed-design wall plates

Types of Jacks

Fixed-design wall plates can accommodate many different types of jacks for different types of data communications media. However, you cannot change a wall plate's configuration once it is in place; instead, you must install a completely new wall plate with a different configuration.
The most common configuration of a fixed-design wall plate is the single six-position (RJ-11) or eight-position (RJ-45) jack (as shown in Figure 2), which is most often used for home or office telephone connections. This type of wall plate can be found in your local hardware store or home center.

Figure 2: Fixed-design plates with a single RJ-11 or RJ-45 jack
Fixed-design wall plates that have eight-position jacks must be carefully checked to see if they are data-capable. We know of retail outlets that claim their eight-position, fixed-design wall plates are "CAT 5e" compliant. They're not. They use screw terminals instead of 110-type IDC connections. If it's got screws, folks, it ain't Category 5e.
Other types of fixed-design wall plates can include any combination of socket connectors, based on market demand and the whims of the manufacturer. Some of the connector combinations commonly found are as follows:
  • Single RJ-11 type
  • Single RJ-45 type
  • Single coax (TV cable)
  • Single BNC
  • Dual RJ-11 type
  • Dual RJ-45 type
  • Single RJ-11 type, single RJ-45 type
  • Single RJ-11 type, single coax (TV cable)
  • Single RJ-45 type, single BNC


Not all wall plate connectors are labeled. Most fixed-design wall plates don't have special preparations for labeling (unlike modular plates). However, that doesn't mean it isn't important to label each connection; on the contrary, it is extremely important so that you can tell which connection is which (vital when troubleshooting). Additionally, some jacks, though they look the same, may serve a completely different purpose. For example, RJ-45 jacks can be used for both PBX telephone and Ethernet networking, so it's helpful to label which is which if a fixed-design plate has two RJ-45 jacks.
For these reasons, structured-cabling manufacturers have come up with different methods of labeling fixed-design wall plates. The most popular method is using adhesive-backed stickers or labels of some kind. There are alphanumeric labels (e.g., LAN and Phone) as well as icon labels with pictures of computers for LAN ports and pictures of telephones for telephone ports. Instead of printed labels, sometimes the manufacturer will mold the labels or icons directly into the wall plate.

Saturday, February 18, 2012

Fixed-Design or Modular Plate | Wall Plate Design

Another design and installation decision you have to make is whether to use fixed-design or modular wall plates. Fixed-design wall plates (as shown in Figure 1) are available with multiple kinds of jacks, but the jacks are molded as part of the wall plate. You cannot remove the jack and replace it with a different type of connector.
Figure 1: A fixed-design wall plate
Fixed-design plates are usually used in telephone applications rather than LAN wiring applications because, although they are cheap, they have limited flexibility. Fixed-design plates have a couple of advantages and disadvantages (as shown in Table 1).
Modular wall plates, on the other hand, are generic and have multiple jack locations (as shown in Figure 2). In a modular wall plate system, this plate is known as a faceplate (it's not a wall plate until it has its jacks installed). Jacks for each faceplate are purchased separately from the wall plates.
Figure 2: Modular wall plates with multiple jack locations
Table 1: Advantages and Disadvantages of Fixed-Design Wall Plates 
Configuration cannot be changed
Simple to install
Usually not compatible with high-speed networking systems
When using modular wall plates, make sure to use the jacks designed for that wall plate system. Generally speaking, jacks from different wall plate systems are not interchangeable.

Tuesday, February 14, 2012

Wall Plate Mounting System

Another decision you must make regarding your wall plates is how you will mount them to the wall. Three main systems, each with its own unique applications, are used to attach wall plates to a wall:
  • Outlet boxes
  • Cut-in plates
  • Surface-mount outlet boxes
The following sections describe each of these mounting systems and their various applications.

Outlet Boxes

The most common wall plate mounting in commercial applications is the outlet box, which is simply a plastic or metal box attached to a stud in a wall cavity. Outlet boxes have screw holes in them that allow a wall plate to be attached. Additionally, they usually have some provision (either nails or screws) that allows them to be attached to a stud. These outlet boxes, as their name suggests, are primarily used for electrical outlets, but they can also be used for telecommunications wiring because the wall plates share the same dimensions and mountings.
Plastic boxes are cheaper than metal ones and are usually found in residential or light commercial installations. Metal boxes are typically found in commercial applications and usually use a conduit of some kind to carry electrical or data cabling. Which you choose depends on the type of installation you are doing. Plastic boxes are fine for simple, residential Category 3 copper installations. However, if you want to install Category 5e or higher, you must be extremely careful with the wire so that you don't kink it or make any sharp bends in it. This is especially true for Category 6A UTP cables, which can be as large as 0.35. Make sure you use boxes that are designed for the cable that you will be using. Also, if you run your network cable before the drywall is installed (and in residential wiring with plastic boxes, you almost always have to), it is likely that the wires will be punctured or stripped during the drywall installation. Open-backed boxes are often installed to avoid bend-radius problems and to allow cable to be pushed back into the cavity and out of reach of the dry-wall installers' tools. If you can't find open-backed boxes, buy plastic boxes and cut the backs off with a saw.
Metal boxes can have the same problems, but these problems are minimized if the metal boxes are used with conduit—that is, a plastic or metal pipe that attaches to the box. In commercial installations, a metal box to be used for telecommunications wiring is attached to a stud. Conduit is run from the box to a 45-degree elbow that terminates in the airspace above a dropped ceiling. This installation technique is the most common wiring method in new commercial construction and is illustrated in Figure 1. This method allows you to run the telecommunications wire after the wallboard and ceiling have been installed, thus minimizing the chance of damage to the cable.
Figure 1: A common metal box with conduit, in a commercial installation

Cut-In Mounting

Outlet boxes work well as wall plate supports when you are able to access the studs during the construction of a building. But what type of wall plate mounting system do you use once the drywall is in place and you need to put a wall plate on that wall? In this case, you should use some kind of cut-in mounting hardware (also called remodeling orretrofit hardware), so named because you cut a hole in the drywall and place into it some kind of mounting box or plate that will support the wall plate. This type of mounting is used when you need to run a cable into a particular stud cavity of a finished wall.
Cut-in mountings fall into two different types: remodel boxes and cover-plate mounting brackets.
Remodel Boxes
Remodel boxes are simply plastic or metal boxes that mount to the hole in the drywall using screws or special friction fasteners. The main difference between remodel boxes and regular outlet boxes is that remodel boxes are slightly smaller and can only be mounted in existing walls. Some examples of remodel boxes are shown in Figure 2.
Figure 2: Examples of common remodel boxes
Installing a remodel box so that you can use it for data cabling is simple. Just follow these steps:
  1. Using the guidelines, determine the location of the new cabling wall plate. With a pencil, mark a line indicating the location for the top of the box.
  2. Using the hole template provided with the box, trace the outline of the hole to be cut onto the wall with a pencil or marker, keeping the top of the hole aligned with the mark you made in step 1. If no template is provided, use the box as a template by flipping the box over so the face is against the wall and tracing around the box.
  3. Using a drywall keyhole saw, cut out a hole, following the lines drawn using the template.
  4. Insert the remodel box into the hole you just cut. If the box won't go in easily, trim the sides of the hole with a razor blade or utility knife.
  5. Secure the box by either screwing the box to the drywall or by using the friction tabs. To use the friction tabs (if your box has them), just turn the screw attached to the tabs until the tabs are secured against the drywall.
Cover-Plate Mounting Brackets
The other type of cut-in mounting device for data cabling is the cover-plate mounting bracket. Also called a cheater bracket, this mounting bracket allows you to mount a wall plate directly to the wallboard without installing an outlet box. Figure 3 shows some examples of preinstalled cover-plate mounting brackets.
Figure 3: Cover-plate mounting bracket examples
These brackets are usually made of steel or aluminum and contain flexible tabs that you push into a precut hole in the drywall. The tabs fold over into the hole and hold the bracket securely to the drywall. Additionally, some brackets allow you to put a screw through both the front and the tabs on the back, thus increasing the bracket's hold on the drywall. Plastic models are becoming popular as well; these use tabs or ears that you turn to grip the drywall. Some also have ratchet-type gripping devices.
Figure 4 shows a cover-plate mounting bracket installed in a wall ready to accept a wall plate. Once the mounting bracket is installed, the data cable(s) can be pulled through the wall and terminated at the jacks for the wall plate, and the wall plate can be mounted to the bracket.
Figure 4: An installed cover-plate mounting bracket

Surface-Mount Outlet Boxes

The final type of wall plate mounting system is the surface-mount outlet box, which is used where it is not easy or possible to run the cable inside the wall (in concrete, mortar, or brick walls, for example). Cable is run in a surface-mount raceway (a round or flat conduit) to an outlet box mounted (either by adhesive or screws) on the surface of the wall. This arrangement is shown in Figure 5.
Figure 5: A surface-mount outlet box and conduit
The positive side to surface-mount outlet boxes is their flexibility—they can be placed just about anywhere. The downside is their appearance. Surface-mount installations, even when performed with the utmost care and workmanship, still look cheap and inelegant. But sometimes they are the only choice.

Friday, February 10, 2012

Wall Plate Location

When installing wall plates, you must decide the best location on the wall. Obviously, the wall plate should be fairly near the workstation, and in fact, the ANSI/TIA-568-C.1 standard says that the maximum length from the workstation to the wall plate patch cable can be no longer than 5 meters (16). This short distance will affect exactly where you place your wall plates in your design. If you already have your office laid out, you will have to locate the wall plates as close as possible to the workstations so that your wiring system will conform to the standard.
Additionally, you want to keep wall plates away from any source of direct heat that could damage the connector or reduce its efficiency. In other words, don't place a wall plate directly above a floor heating register or baseboard heater.
A few guidelines exist for where to put your wall plates on a wall for code compliance and the most trouble-free installation. You must account for the vertical and horizontal positions of the wall plate. Both positions have implications, and you must understand them before you design your cabling system. We'll examine the vertical placement first.

Vertical Position

When deciding the vertical position of your wall plates, you must take into account either the residential or commercial National Electrical Code (NEC) sections. Obviously, which section you go by depends on whether you are performing a residential or commercial installation.
In residential installations, you have some flexibility. You can place a wall plate in almost any vertical position on a wall, but the NEC suggests that you place it so that the top of the plate is no more than 18 from the subfloor (the same distance as electrical outlets). If the wall plate is intended to service a countertop or a wall phone, the top of the plate should be no more than 48 from the subfloor. These vertical location requirements are illustrated in Figure 1.

Figure 1: Wall plate vertical location
The vertical heights may be adjusted, if necessary, for elderly or disabled occupants, according to the Americans with Disabilities Act (ADA) guidelines.
Remember that the vertical heights may vary from city to city and from residential to commercial electrical codes.

Horizontal Position

Wall plates should be placed horizontally so that they are as close as possible to work-area equipment (computers, phones, etc.). As previously mentioned, the ANSI/TIA-568-C.1 standard requires that work-area cables should not exceed 5 meters (16). Wall plates should therefore be spaced so that they are within 5 meters of any possible workstation location. This means you will have to know where the furniture is in a room before you can decide where to put the wall plates for the network and phone. Figure 2 illustrates this horizontal-position requirement.

Figure 2: Horizontal wall plate placement
When placing telecommunications outlets, consider adding more than one per room to accommodate rearrangement of the furniture. It usually helps to "mirror" the opposing wall-outlet layout (i.e., north-south and east-west walls will be mirror images of each other with respect to their outlet layout).
Another horizontal-position factor to take into account is the proximity to electrical fixtures. Data communications wall plates and wall boxes cannot be located in the same stud cavity as electrical wall boxes when the electrical wire is not encased in metal conduit. (A stud cavity is the space between the two vertical wood or metal studs and the drywall or wallboard attached to those studs.)
The stud-cavity rule primarily applies to residential telecommunications wiring as per the ANSI/TIA-570-B standard. The requirement, as illustrated in Figure 3, keeps stray electrical signals from interfering with communications signals. Notice that even though the electrical outlets are near the communications outlets, they are never in the same stud cavity.

Figure 3: Placing telecommunications outlets and electrical wall boxes in different stud cavities

Wednesday, February 8, 2012

Wall Plate Design and Installation Issues

When you plan your cabling system installation, you must be aware of a few wall plate installation issues to make the most efficient installation. The majority of these installation issues come from compliance with the ANSI/TIA-570-B (for residential) and ANSI/TIA-568-C.1 (for commercial installations) telecommunications standards. You'll have to make certain choices about how best to conform to these standards based on the type of installation you are doing. These choices will dictate the different steps you'll need to take during the installation of the different kinds of wall plates.
The National Electrical Code dictates how various types of wiring (including power and telecommunications wiring) must be installed, but be aware that NEC compliance varies from state to state. The NEC code requirements described should be verified against your local code requirements before you do any structured cable system design or installation.
The main design and installation issues you must deal with for wall plates are as follows:
  • Manufacturer system
  • Wall plate location
  • Wall plate mounting system
  • Fixed-design or modular plate
In this section, you will learn what each of these installation issues is and how each will affect your cabling system installation.

Manufacturer System

There is no "universal" wall plate. Hundreds of different wall plates are available, each with its design merits and drawbacks. It would be next to impossible to detail every type of manufacturer and wall plate, a few examples of the most popular types. The most important thing to remember about using a particular manufacturer's wall plate system in your structured-cabling system is that it is a system. Each component in a wall plate system is designed to work with the other components and, generally speaking, can't be used with components from other systems. A wall plate system consists of a wall plate and its associated jacks. When designing your cabling system, therefore, you must choose the manufacturer and wall plate system that best suits your present and future needs. It is best to stay with one common wall plate system design for all of the workstation's outlets.

Tuesday, February 7, 2012

Labeling | Modular Wall Plates

Just like fixed-design wall plates, modular wall plates use labels to differentiate the different jacks by their purpose. In fact, modular wall plates have the widest variety of labels—every modular wall plate manufacturer seems to pride itself on its varied colors and styles of labeling. However, as with fixed-design plates, the labels are either text (e.g.,LANPhone) or pictures of their intended use, perhaps permanently molded in the plate or on the jack.