Q: Who can I contact, or where can I get more information concerning the installation of 25-pair Category 5 cabling? I`m in the process of designing cabling- installation specifications that will be incorporated into all new and renovated building projects on my base. I have read all of the tia/eia-568a, eia/tia-569, tia-eia-606, tia/eia-607, TSB 67, and TSB 75 standards, and I understand that the standards are currently under revision. However, I cannot find references to installing 25-pair cable; that is, information on good installation practices.
I am planning to terminate all of the unshielded twisted-pair (UTP) horizontal cabling to a patch panel, then have another patch panel with a 25-pair Category 5 cable terminated on the back of it, feeding to Category 5-rated 66-type connecting blocks. This configuration would allow for the interface of telephone equipment. The only experience I have with this type of installation is what I have read. Can you help?
Ellis F. Baumer
US Air Force
Vandenberg AFB, CA
A: For installation guidance on 25-pair Category 5 cable, you need to contact the cable manufacturer. You are correct that some of the standards are currently under revision, but that is always the case. For example, tia/eia-568a was published in October 1995 and the Telecommunications Industry Association (TIA) TR41.8.1 working group has balloted three addenda and already begun work on tia/eia-568b.
As for your proposed design, it violates the tia/eia-568a, Annex E link model. There are too many pieces of termination hardware in the link. For a good overview of design methods, I suggest that you read the bicsi (Tampa, FL) Telecommunications Distribution Methods Manual (tdmm).