NEC nd-20292 manual Site Preparations and MDFlIDF, Construction

Table 200-15DTA-E Unit / RS232C Connector Pin Configuration

PIN # SIGNALFLOW1 DESCRIPTION

with the RS-232C interface.

SECTION 230

SITE PREPARATIONS and MDFlIDF

CONSTRUCTION

230.1 GENERAL INFORMATION

This section presents a survey of the planning details that should be considered prior to installing an Electra Mark11 System. Detailed planning in advance of the

actual installation will help ensure that minimum

time and cost are incurred and, concurrently, will cause a minimum disruption of the customer’s business activities. ‘Additional benefits of a well planned and

executed installation include flexibility for changes

and expansion at minimum cost, efficient maintenance, and increased customer satisfaction.

230.2SITE SURVEY

In most cases, a survey of customer premise is needed

to develop a cost estimate of the installation. The preliminary data should be used in the site selection of the Main Distribution Frame (MDF). A second visit to

the job site may be necessary to obtain exact dimensions of the area selected for the MDF, cable lengths, and possible IDF locations. This information will provide the basis for planning an orderly and efficient installation.

For example, the collected data about the job site will

generally permit the MDF to be partially preassembled at the installer’s shop, which helps to minimize the time spent at a customer’s premises.

Preassembling the MDF and IDF is especially advantageous for those jobs where the MDF, or IDF, must be placed in an area that is awkward for this type of work.

ND-20292

CHAPTER 2

APRIL, 1990

230.3SITE LIMITATIONS

Installation of a telephone system is seldom a

straightforward routine procedure. The uniqueness of each customer’s situation requires a tailored approach to each job. In selecting a permanent site for the MDF, the installer may encounter problems such as the following:

lLimited space is available and must be used, regardless of its suitability.

0The available space may be adequate but may pose one or more environmental hazards.

0The proposed location has limitations, such as, insufficient lighting, or the lack of a suitable ground, for grounding the CCUs.

Whatever the nature of the adversities encountered, the installer must make the necessary decisions to arrive at the best possible solution for the equipment

being installed and the customer. It is beyond the scope of this document to cover all possible situations and solutions. The following are general guidelines, precautions and actions which should be observed to help make the installation decisions.

NOTE: Certain specific requirements and precautions, if not followed, will impair the reliability of the system.

230.4 SITE SELECTION CONDITIONS

The following conditions should be met at the site chosen for mounting the Central Control Unit (CCU).

A. Up to three CCUs are normally wall mounted to protect against accident or flooding. When this is done the fourth CCU must be wall mounted but separated from the other three CCUs by an additional base panel placed atop the third CCU. Then the top panel is mounted on top of the 4th CCU. When floor mounting is used with 4 CCU’s there is no need for a second base panel, however, the 4th CCU must be secured to a wall. Use of a

314” fire retardent plywood backboard is recommended for this purpose.

B. The CCU should not be located directly beneath

pipes, due to the possibility of leaks or

condensation causing damage to the Electra Mark11 equipment.

C.The area in which the CCU is to be located must be free of corrosive and inflammable gases, excessive chemical or industrial dusts, and other materials

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