4. Cable
Installation
and
Connection
4-1.
Cable Installation
4-1-1. Wire
type, number of wire pairs and number of
individual wires are to be determined for in-
dividual sections of the wiring system accord-
ing to the guidelines set down below.
4-wire telephone cables unshielded 2 twisted
pair cables are to be used for wiring between
stations and the intermediate or indoor boards.
As a rule, private branch cables are to be
for wiring between indoor terminal boards,
intermediate terminal boards, main terminal
boards, etc.
Indoors, the number of cables that can be run
through a conduit is, as a rule, less than
200 pairs.
Outdoor wires should be used where wiring
passes through inaccessible areas such as in
ceilings or under floors. Indoor wires may
also be used, however, in cases where there
is no risk of deterioration due to exposure
to heat, etc.
The number of cable pairs laid should be
determined considering the possibility of
future expansion of the system.
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