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.

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

Warning

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

Labeling

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.

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 

Advantages	Disadvantages
Inexpensive	Configuration cannot be changed
Simple to install	Usually not compatible with high-speed networking systems

Tip

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.

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.