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3-24
Conditions
It is the installer's responsibility to assure that CO line connections are made in such a
way that proper CO Hunting will sequence from the first CO line button to the last, in
order on key telephones.
Typically, the Telco service provider provides lightning protection on the premises at
the service entrance.
Test each CO Line at the MDF for dial tone, correct ringing sequence, Telco number
assignment and polarity.
6. Station Cabling
Floor plans should be developed to aid in proper station cabling in a star (home run)
configuration from the KSU. The cables are run from the station locations to the STN
block at the MDF.
Both ends of each cable should be labeled with the station's circuit number. The circuit
number designates the station port position in the KSU.
When the system is initialized, the intercom numbers are assigned in order from Port-1
(intercom number 10) to Port-24 (intercom number 33) as each Module is installed (refer
to
Table
Running Cable
From the MDF location, run unshielded, 3-pair (6-conductor) twisted cable to all key
telephone locations and DTMF single-line telephone locations.
Follow these guidelines:
Install proper type cable for the application according to the National Electrical Code
and local building codes.
Avoid cable runs parallel to fluorescent light fixtures or AC lines not in conduit. If
these obstacles are unavoidable, run the cables across them at right angles.
Do not run station cables inside electrical conduit already occupied by AC wiring. To
do so is a violation of the National Electrical Code.
Do not run station cables near equipment with electric motors or through strong
magnetic fields, such as those generated by large copy machines, arc welding
equipment, heavy motors, etc.
Do not place station cables where they can be stepped on or where they can be
rolled over by office furniture.
If using multi-pair (25-pair) cable runs to multiple station locations do not include AC
ringing single-line sets, AC-ringing auxiliary equipment, or CO lines in a cable being
If incoming CO lines Hunt from a main telephone number and are also used for outgoing
(both-way CO line) service, always prioritize the incoming line order so that the last choice
incoming trunks appear on the higher number CO line positions. This is because the system
automatically selects idle trunks for outgoing calls, by searching from CO line 18, to CO line
17, and so on to CO line 1. This technique may avoid a head-on or Glare condition where a
user trying to place an outgoing call inadvertently answers a ringing line.
3-12).
Use shielded cable if RF1/EF1 is expected.
DHS-E Installation
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