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Subsidiary connection (piggy-backing)
Subsidiary connection
3.1
{piggy-backing)
Before connecting 2+8 to a host PABX the approved maintainer should
be consulted. 2+8 may only be attached to P ABXs given in List C of the
DTI document 84011 I.
When the 2+8 is connected to a host PABX, it is a mandatory
requirement that locking bars 2A or 3A are fitted to extension wall
sockets serving extensions 20 and 21, holding the telephone plugs
captive.
The 2+8 may be connected to a host PABX by connecting an extension
from the host P ABX to the exchange line port of the 2+8. The connection
details are the same as those given in paragraph 2.1.9 for the exchange
line, except that for Exchange line read Host PABX.
It will be necessary to select the forward recall type for either Earth or
Time Break recall depending on the host PABX. This is selected by DIL
switch on the CCU PCB. See paragraph 2.1.13 and Figure 2.5. See also
paragraph 2.1.14 for setting of the LKl and LK2 host PBX straps.
If Earth Loop Recall is selected it is important that the polarity of the
Note
exchange line A and B wire is correct or the recall facility may not work.
Exchange line A and B wires must be terminated as labelled on the
exchange line IDC terminals. See paragraph 2.1.9.
3-1
TPU 1371Issue3(4/91)
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