System overview
EST3 Installation and Service Manual 1.29
Network applications
This section deals with the initial layout of the network cabinets
as well as application configurations for the basic network
modules.
Network layout
The first task for the system designer is locating the equipment
cabinets throughout the project. The objective when locating
cabinets is to maximize the per cabinet coverage of the facility
while minimizing hardware cost. The following general
information should be used as a guide to designing the system.
The per cabinet coverage is, in some part, based upon the type of
project being designed. In a high rise building installation that
requires an audio emergency voice communication system, the
problem becomes how many floors can be served by a single
cabinet. In a campus style installation, there may be one or more
cabinets per building, depending on building size.
Cabinet coverage
The following factors govern how much area a single cabinet can
cover:
Cabinet capacity: Depending on the installed equipment, the
largest backbox available can have 21 module spaces and 3
chassis spaces. Is this enough cabinet capacity to house the
equipment required to cover the proposed area?
Available current per cabinet: Does the proposed number of
large current components (audio amplifiers and 24 Vdc
notification appliance circuits), in addition to the required
module currents, exceed the available 28 amps per cabinet or
60-Ah battery capacity?
Notification Appliance Circuit voltage drop: Does the distance
from the cabinet to the last strobe, horn, speaker, etc. exceed the
acceptable limits?
User interface requirements: Depending on the installed
equipment, the largest backbox available can have 19 module
displays installed. Will this provide enough capacity for the
required control/display module functions?
Distance between cabinets: Does the wiring length between
any three cabinets exceed 5,000 ft. (1,524 m)?
System capacity of 64 cabinets per network: Does the
proposed system require more than 64 cabinets?
Cost of installation labor and materials: Is it cheaper to install
a smaller cabinet and service the floor above and below the floor
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