Avaya 6424D+M User Manual page 96

Two factors govern the size of the MDF: the number of cable pairs to be terminated and the type of
cross-connect hardware used. Since the recommended cross-connect hardware for Generic 2 with
universal modules is the 110A, you need only to calculate the number of cable pairs that must terminate
on the MDF and the number of 110A cross-connect blocks needed to terminate those pairs to arrive at
the size of the MDF.
This section helps you calculate the number of cable pairs terminating at the MDF by determining what
effect the four major fields of the MDF have on its size. These four fields are as follows:
Network services (CO trunks) field with green labels
Auxiliary equipment and miscellaneous field with yellow labels
Equipment (switch) port field with purple labels
Distribution field with white labels
A fifth field, with blue labels, may be required for some installations. This field terminates 4-pair
installation cables that connect the MDF directly to the information outlets (IOs)at workstations.
The guidelines for sizing each field follow.
Network Services (CO Trunks) Field
The network services field uses green labels; it terminates CO cables. Cabling for analog network
services is cross-connected to the green field from an RJ21X or an RJ2GX interface. This cabling
requires sneak-current protection in addition to the standard electrical protection that the telephone
company provides.
The total number of pairs in the network services cable is governed by the number of pairs that the
customer needs to connect to the network. It is also governed by the number of pairs that the telephone
company supplies. For example, if the customer needs to connect 750 pairs to the network, and the
telephone company supplies a 900-pair cable, the green field must be sized to terminate 900 pairs.
For some installations, digital signal level-1 (DS1) transmission capabilities also may be needed. When
the DS1 connection is part of the installation, then a digital signal cross-connect (DSX) may be required.
If a DSX is required, use the 800 series DSX as described in 800 Series DSX — General Description,
DSX System (365-301-102).
Auxiliary Equipment and Miscellaneous Field
The auxiliary field uses yellow labels; it terminates auxiliary equipment cables. This includes
emergency transfer units, recorded announcement units, recorded dictation units, loudspeaker paging
units, and radio paging units. The auxiliary field also accommodates miscellaneous cabling that is not
associated with ports, such as cables from CC cabinets, console cables, and alarm cables. Therefore, the
size of the yellow field varies depending on the amount of auxiliary equipment installed and the number
of miscellaneous cables terminated.
Allocate space on the yellow field for the termination of a minimum of 300 pairs. Allocate additional
space in 300-pair groups for each auxiliary cabinet installed with the system. Increase the field size
beyond these minimums as actual needs dictate.
MDF/lDF DESIGN: DEFINITY GENERIC 2 WITH UNIVERSAL MODULES
7-11