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Installation procedures
Extension telephones
2.1.6
The 2+8 is approved for use with (green spot) approved telephones,
which may be connected to any extension. The system uses Master-type
line jacks at the telephone instrument irrespective of the telephone or
Systemphone used.
All approved extension telephones on the system must be fitted with a
working Earth recall key. It should be noted that a local earth is not
needed at the telephone and that the recall signal to the CCU from the
extension telephone does not apply a physical earth condition.
The extension Telephone may use eitherTouchTone or Pulse signalling.
It should be noted that the system is transparent to the extension
telephone when it is switched through to the exchange line ports. Thus,
telephone signalling must be compatible with the serving exchange or
hostPABX.
Cabling and wiring
2.1.7
Do not exceed the following resistance limits when connecting
extensions to the CCU (using 0.5mm
- 25
- 50
Great care should be taken when selecting the cable routes to ensure
that the cabling complies with the current edition of the IEE wiring
regulations. This document details the separation requirements between
telecommunications cables and cables carrying mains supply voltages.
Generally the route chosen must be such that:
Telecoms cables must not be drawn into the same conduit or duct as
•
cables carrying mains voltages.
Telecoms cables must not be run or fixed adjacent to cables carrying
•
mains voltages. Where a telecommunications cable has to run in parallel
or cross a mains cable an appropriate amount of cable separation must be
maintained as specified in IEE regulations.
Even if a cable run complies with IEE requirements long parallel runs
Note
adjacent to mains cables can induce mains hum.
Cables should not be run through any area designated as having an
•
explosive atmosphere.
The extension and exchange line cables must be of twisted-pair
construction using insulated tinned copper wires of nominal 0.5mm
cross-sectional area. It is important that this size and type of wire is used
as incorrect types could result in unreliable connections.
The extension and exchange line cables enter the CCU at the right-hand
side of the CCU when viewed from the front of the case. Pass the cables
through the cable slot in the CCU case adjacent to the relevant Insulation
displacement connectors.
The cables should remain sheathed inside the CCU housing within reach
of the JDC. Guide the cables neatly into the channel space between the
JDC blocks and the CCU case side.
2-5
or 150m for System phone extensions
n
or 300m for approved telephone extensions.
n
2
tinned copper conductor):
2
TPU
1371Issue3(4/91)
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