Three types of patch panels (wireless, electronic, and intelligent)have benefits and drawbacks, depending on the application.

When it comes to making a move, add, or change in a voice/data cable plant, sending a technician to perform physical changes at a patch panel in a wiring closet is one of the most time- and cost-intensive operations in the overall support of a communications system. In fact, one industry research group recently estimated that the cost to maintain local area networks (LANs) consumes 84% of a network manager's budget, 44% of which is spent on physical management and troubleshooting.

There are new types of patch panels currently available that can help reduce the time and cost associated with these activities. These "unconventional" patch panels each have their benefits and drawbacks, depending on the application at hand.

Some definitions

Before getting into the subject of what's out there in the way of electronic patch panels, let's first attempt to define the term. An electronic patch panel is a device that enables cross-connecting electronically; that is, without the necessity of making by hand any physical changes using patch cords or other cross-connect components. This definition also implies the ability to make such changes from a centralized station or terminal such that the patch panels controlled in this manner can be remotely monitored and/or configured by a central operator. The promise of this technology could be very appealing, since it would effectively eliminate the need to dispatch technicians to wiring closets every time a cross-connect of some kind (i.e., a move, add, or change) is required.

The ideal electronic patch panel should also be very flexible and very intelligent. It should not only enable the making of distributed cross-connections from a central point, but should also support mixed media cross-connections as well. For example, you may, in some cases, want to cross-connect horizontal unshielded twisted pair cables (UTP) to fiber in the backbone or, at a minimum, make UTP-to-UTP connections. In any event, the ability to support opti-electronic transitions in media would seem to be of some value in certain cases.

In practice, an intelligent, electronic patch panel would give a network manager the ability to make cross-connections from any circuit in horizontal wiring to any circuit in the backbone subsystem without ever having to leave his or her desk. Moreover, the ideal system would also enable cross-connections between two or more circuits in the horizontal subsystem, up to and including daisy chained-circuits when required.

An example

Let's consider a simple example. Let's say we're dealing with a situation where a well-designed structured cabling system is in place. And let's say that this system provides for a standard faceplate having four RJ-45 jacks at each workstation. At one such station, you therefore would have four hard-wired 4-pair connections back to the wiring closet. Now, let's assume that each user's connection to the wiring closet is terminated onto what we have described as electronic patch panels. Let's also assume that the cabling system in our example also features the usual mix of copper and fiber in the backbone (copper for voice, and fiber for everything else).

Now, if we look at a typical cross-connect situation for an average user in this scenario, we might expect to find that one RJ-45 connection at the wiring-closet end is cross-connected to a circuit that supports "data," while another is cross-connected to a circuit that supports "voice." The third and fourth jacks might not be in use, but could be at some future time, if and when applications appear.

Let's assume that a need comes up for the third jack at a workstation, thereby requiring the cable manager to establish a new cross-connection to support a new application, a dial tone line to a desktop for a fax machine, for example. Rather than dispatching a technician with a set of tools and, hopefully, accurate documentation, the cable manager in this scenario (assuming electronic patch panels are in place) simply turns to the cable management/patch panel control system and makes the change on his or her screen within seconds of having received the request. Once completed, the change is instantly recorded, thereby updating the cable documentation in the same stroke.

Our example not only illustrates the power of electronics when applied to an otherwise physical task, but also illustrates the overlap of this technology with another one: cable management systems. But while cable management systems are a relatively mature technology at this point, the same can not be said for electronic patch panels. There are, however, some interesting developments out there that suggest it's time to start paying attention to this emerging technology. Let's take a look at what products are currently available to you.

Product classifications

A high level review of what's out there in terms of what we'll generally refer to as "unconventional" patch panel technology yields products in at least three different categories. In spite of their differences (which we'll describe), all products in these categories have one thing in common: they are designed to minimize, if not totally eliminate, the need to physically make moves, adds, and changes as traditionally done by technicians using patch cords and cross-connect wires in wiring closets.

The three categories of products, according to our view of the world, are as follows.

* Wireless patch panels

* Electronic patch panels

* Intelligent patch panels

Wireless patch panels. Products in this category fit the description of "unconventional" patch panels, but are far from electronic or intelligent. They are, in fact, passive devices. This is an important distinction compared to the other two categories, which themselves may be wireless, but are not passive.

Wireless patch panels are also wireless only to the extent that they avoid the use of external patch cords to achieve cross connections. Instead, they rely on internal cross-connections using hard-wired modules that connect "input conductors," or jacks, to "output conductors." This results in a straight-through cross-connection of media such that each conductor's identification is maintained all the way through the cross-connected circuit (e.g., the Tip of pair I is maintained; Ring of pair i is maintained; Tip of pair 2 is maintained; etc.). Wireless patch panels designed for copper connections are usually based on 2-, 4-, or 8-wire configurations (i.e., for UTP cable plants).

With wireless patch panels, the assumption is that "normal" prevails for most jacks most of the time, and patch cords should only be used to make changes or to deal with the exceptions. Patch cords, therefore, can be used with wireless systems, but only when deviations from the norm are required. Insertion of a patch cord into a wireless patch panel breaks the internal cross-connection, thereby freeing the input channel for reassignment to another output channel at the user's discretion.

All of the physical administration of a wireless patch panel must still be performed on a remote basis by technicians inside wiring closets. Wireless systems, according to our classification here, are therefore not addressable by remote devices and can not be controlled from a central management station of any kind. Wireless systems are also built using passive components and are not electrified in any way. (In terms of appearance, wireless patch panels closely resemble conventional patch panels and are comprised of RJ-type jacks on their front panels.)

Electronic patch panels. Unlike wireless patch panels, electronic patch panels are active in the sense that they are electrified. [ILLUSTRATION FOR FIGURE 1 OMITTED]. They, therefore, are capable of sensing, capturing, and storing certain operating or status conditions, which can then be reported to the network manager for proper handling. Electronic patch panels, again according to our classification, can not, however, be managed from a remote, centralized station, and still require physical handling by technicians inside wiring closets.

Examples of functionality common to electronic patch panels include "sensing" of patch cord insertion or removal from a jack, after which insertion/removal "events" are captured and reported to a network manager. Other examples include the ability to turn LED lights on or off around specific jacks to help guide technicians perform cross-connect work when changes are required. In general, a well-rounded electronic patch panel system will provide a variety of status and change-oriented reports, and may also be used to sense other systems of importance in managing the physical environment in wiring closets (e.g., cooling fans, thermometers, alarm systems, etc.).

Intelligent patch panels. This category of "unconventional" patch panel, as shown in Fig. 2, includes devices with all of the attributes of wireless and electronic systems. As its name implies, the intelligent patch panel is fully manageable from a remote, centralized station. Products that fall into this category support a variety of automated functions including the following.

* Centralized online control: The ability to make cross-connection changes and assignments from a remote, centralized station, thereby eliminating the need to send technicians to wiring closets. This also implies the total elimination of patch cords, since all cross-connections are made through internal electronics.

* System monitoring and reporting: The ability to activate certain sensor functions, as in the case of electronic patch panels, along with powerful reporting capabilities for network management.

* Automated recordkeeping: Fully integrated cable management system such that moves, adds, or changes are controlled by the system as well as recorded for full "as-built" documentation reporting capabilities. Systems of this type make heavy use of user-friendly graphical user interfaces (GUIs) as well.

* Disaster recovery: The ability to withstand power failures using backup power supplies, robust memory systems, and secondary/back-up path selection.

* Security: The ability to password-protect configurations and associated databases is also common to these and all other intelligent systems.

Equipment analogous to intelligent patch panels

In many respects, the concept and functions of intelligent patch panels are very analogous to other forms of switches and intelligent hubs. In the voice arena, every PBX or telephone system out there minimally performs internal cross-connections between stations (extensions) and trunks (phone lines). Even the process of establishing station-to-station connections or multistation or conference calls resembles the same kind of flexible connectivity implied by our definition of intelligent patch panels.

In the world of high speed data networks, intelligent hubs (sometimes referred to as wiring concentrators) also provide dynamic internal cross-connections when used in conjunction with remote, centralized management software. Using systems of this type, a network manager can electronically group several network users together in one "logical" network on one day, and on the next, totally redefine the group such that a different mix of users results. This can all be done without having to dispatch technicians to wiring closets.

Performance considerations

In spite of the general appeal to the products discussed here, none of them offer a panacea from a functional standpoint, and all have their limitations. First of all, any of the products currently in place on the market are media-bound. In other words, they are all either copper-only or fiber-only in their makeup. This may represent a drawback in cases where users require multimedia connectivity such as needing to extend copper circuits over long distances where fiber may be the preferred choice.

All of the systems currently on the market also appear to be rather application-bound. In other words, the intended applications seem to be restricted to data-only requirements. This appears to be less the case with the wireless patch panels and more the case with the others. The granularity of treatment required for voice where, for example, 1-pair cross-connections are often required, would appear to be either impractical or cost-prohibitive based on how these systems are built and configured.

And lastly, even when it comes to data network performance, this technology is still somewhat behind the rest of the industry. If we assume that the expectation in the industry is that 100-megabit per second (Mbps), or Category 5 UTP, performance levels are required, products in each of the three categories discussed above roughly break out as shown in Table 1.

What's interesting about this performance analysis is that only the "unconventional" patch panel that still relies on "conventional" cross-connection methods rates at the industry-standard level of Category 5 performance. This is not surprising since Category 5 systems are very sensitive to deviations in crosstalk and attenuation. Unconventional methods of establishing and maintaining circuits appear to have a ways to go before these alternative technologies can stand up to the task of supporting continuous data streams at 100 Mbps. At this point in time, only one manufacturer of "intelligent" patch panels indicates that its products have been tested successfully at 100 Mbps, but have not yet been certified as such. This could prove to be problematic in the short run, since all of the industry standards for certification are based on the use of conventional connecting hardware, not unconventional electronic switches.

In any case, the nature of the products described here as electronic patch panels is such that all electronic functionality is essentially nonintrusive. In other words, the key functions of sensing and reporting really do not interfere with or participate in the cross-connections themselves. And certainly the presence of LED lights and so forth are external to the connectivity scheme inherent to these devices. Thus, it's no surprise that performance for these products are in line with the mainstream of traditional patch panels, and are higher than products in the other two categories.

Cost considerations

In looking at cost, we chose one representative product from each of the three categories defined above. Our attempt to reduce the comparison to equal terms is based on the notion of a typical cost per port. Our findings are shown in Table 2.

Well, as they say, "you get what you pay for." The lesson here is that with wireless and electronic patch panels, you're still paying for the performance of physical moves, adds, and changes by people (dispatching technicians to wiring closets, their salaries, etc.). With fully intelligent patch panels, you're not. Thus, the real costs of wireless and electronic systems also include the traditional cost of the human resources required to work with them. But given the still low levels of performance for intelligent systems coupled with their severe application constraints (data only), we would conclude that these systems have a long way to go before they begin to outweigh the flexibility offered by traditional connecting hardware schemes.

Nevertheless, it's definitely time to start watching this technology. In this business, everything can change in the course of a week!