Avaya 6424D+M User Manual page 35

2-12
MDF/lDF DESIGN: SYSTEM 85 AND DEFINITY GENERIC 2 WITH TRADITIONAL MODULES
beyond these minimums as actual needs dictate.
Equipment (Switch) Port Field
The equipment port field, which uses purple labels, is where the cables from the equipment ports
terminate. Two factors govern its size. The first is the type, usage, and number of port carriers; the
second is module needs, since all ports from an equipment module must be colocated.
System 85 uses two types of port carriers and a maximum of 12 port carriers in one module. One carrier
is the universal port carrier, which is coded J58888A. It has eight 25-pair cables. The other carrier is
the DS1/MFAT carrier, which is coded J58888N. Depending on how it is used, it has two, four, or
sixteen 25-pair cables. The DS1/MFAT carrier has two 25-pair cables when the carrier is holding
ANN11 (DS1 line/trunk interface) circuit packs. It has four 25-pair cables when it is holding ANN15
(RGI) circuit packs. It has sixteen 25-pair cables when it is holding standard port circuit packs.
Modules usually contain the same number of port carriers. To calculate the number of wiring blocks
required for the entire port field, multiply the number of modules by the number of wiring blocks
required to serve one module. Allow for the termination of 1800 pairs for the port field. Increase or
decrease the number in 300-pair increments according to actual needs.
Distribution Field
The distribution field, which uses white labels, is where all of the distribution cables terminate.
Distribution cables are the cables that run from the MDF in the equipment room to the IDF in the
closets. (They are sometimes called "house," "backbone," "riser," "campus," or "black" cables. This
document calls them "distribution cables.")
The Premises Distribution System Design Guide (555-400-602) presents several approaches to sizing the
distribution cables based upon the needs of the customer. These approaches apply to the sizing of
distribution cables for a System 85, with the exception of the following guidelines:
Size the distribution cable so that each workstation is allotted a minimum of two cable pairs.
Allow the 25th pair in each 25-pair bundle to serve as a spare.
Allot four cable pairs for each workstation if the customer requests single-point administration and/or
plans to use 110P hardware.
Terminate large numbers of spare pairs requested by the customer on a specially designated area of
the MDF. This guideline is for efficiency since the spare pairs artificially increase the size of the
distribution field.
Installation Cable Field
The installation cable field, which uses blue labels, is where cables from the information outlets (IOs)
terminate directly to the MDF. (Remote-module MDFs require fields labeled purple and blue when
installation cables are connected directly to them.) When the installation cable terminates in the
equipment room, size it and plan for its termination as you would for closet terminations. That is, allot
one 4-pair D-inside-wiring (DIW) cable for each workstation. Allot two 4-pair DIW cables for
workstations that use a separate IO for a data connection.