Courtesy of Cabling Business Magazine
Creating zones is a very common-sense approach to cabling a large partitioned area covering an entire floor, or a building that is multilevel making it hard to run horizontal cabling from one closet on a floor to another. Zone cabling is not a new idea, but with the advent of cheaper switch equipment, Voice over Internet Protocol (VoIP) and wireless technology, it makes more sense to implement.
A good example is a bank building that my company cabled. The building had large windows and contained six levels that werent actually floors, but were accessed by short stairways. It was a beautiful building, but there was only one room in the basement for the MPOP (main point of resence for the local service provider) computer room, telephone switch, electrical room, etc. Fortunately, there were duct channels embedded in the concrete floors of each level. However, they had only one 2 conduit chase for voice and data cabling that ran from the one Telco room to each level accessing the underfloor channel system. It entered the system at one end of the floor. The underfloor duct channel also supplied electrical power via another 2 conduit from the same telephone/electrical room in the basement.
At each desk location, a hole was drilled into the underfloor duct, and a monument or tombstone with power, voice and data outlets was provided.
Since this was before VoIP became popular, we had to cable for a traditional PBX switch. Fortunately, the phone switch required only one pair per voice phone set. The installers ran one 10- pair, and one 25-pair UTP feed cables to each floor, to a centrally located junction of the underfloor duct that was in a partition area. This gave us at least a 40 percent growth on each level for voice stations. With the copper feed cables, we ran one 3 1/4-inner-duct tubing with a pull tape and 6 strand multimode breakout cable in each inner duct tubing. The conduits were completely filled.
At the central location on each floor level, we used a small 3 by 19- freestanding rack and used a 19-rackmounted 200-pair 110 blocks to terminate the feed cables. We used another rack mount 200-pair 110-block for terminating the Category 5 voice station cables. All the Category 5e data cabling was terminated onto a pre-wired 110 to RJ-45 patch panel. We installed a rackmounted fiber enclosure beneath the patch panel and mounted an Ethernet 100BaseT switch below the patch panels. All of the voice stations were cross connected to the copper feeds, which in turn were cross connected down in the MPOP/MDF and into the switch extension blocks. Fiber backbones were terminated with SC connectors, and connected to the Ethernet switches with fiber patch cables and then each switch was connected via Category 5e patch cables for the data stations. This is only one example of zone cabling.
Other examples include electronic hardware, such as Ethernet switches, as illustrated in Figure 79. They may also contain two patch panels: one for the feed cable from the MDF, IDF or tele-communications closet; and, the other patch panel has all the horizontal station cables that run to the drop or workstation locations in the designated zone area. As illustrated in Figure 80, these smaller zone-patching hubs can be contained in an enclosure or in a concealed drop ceil-ing panel designed for that purpose.
Basically, the need to shorten cop-per horizontal cable runs to facilitate the easy MACs (moves, adds or changes) process and lower installation costs is another factor. Another reason is plac-ing Layer 3 or higher Ethernet switches in areas with a specific domain address. Zone cabling also makes the deploy-ment of wireless access points much easier, as well.
Cheryl Gorman writes fiction, non-fiction and offers a range of editorial services. She can be reached at cherlamour@aol.com. Mike Gorman has 25 years experience in the industry and was the president of a cabling company for 16 years. He writes technical books on cabling and offers accredited courses to colleges. He is also a certified wireless network administrator (CWNA) and a proxim certified broadband engineer (PCBE). He can be reached at mgdcabler@comcast.net.
