Cabling The Unit; Connecting The Extensions - BT Versatility Installation And Maintenance Manual

BT Versatility
Installation and Maintenance Manual

Cabling the unit

All Line and Extension circuit cabling is inserted from the top of the unit. There are
breakouts as shown on the top of the unit to facilitate routing of cables into the MDF
area.
Cabling Break outs

Connecting the extensions

It is recommended that all extensions be cabled with 2 pairs. The Featurephones use all
four wires and standard phones use the a,b pair only.
Do not exceed the following resistance or distance limits when connecting extensions to
the System Unit. (The distances listed assume 0.5mm-tinned copper conductor is used).
• 100 Ohms, or 500 metres, for system Featurephones
• 200 Ohms, or 1.4 kilometres, for a standard telephone
• 336 Ohms, or 2 kilometres, for a standard telephone connected to the external
extension on the Options Module.
The Extension cables must be of twisted-pair construction, using insulated tinned copper
wires of nominal 0.5 mm cross-sectional area. Category 5 cable must be used for all
ISDN installations.
It is important that this size and type of wire is correct since incorrect types can result in
unreliable connections. Care should be taken to ensure that the cabling complies with all
relevant cabling requirements.
Run cable from each Extension location to the Main Equipment. Pass the cable through
the cable entry hole in the CCU or Expansion Module and terminate the Extension
wiring at the appropriate connector in accordance with the table overleaf.
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