Specifications

3-70 System Wiring
Chapter 3 - System Installation
XTS-IP - Installation Manual December 2005
Power Failure Transfer Unit Wiring
The Power Failure Transfer Unit (PFTU) is wired from the 25-pair connector to the MDF, cross
connected to the CO Line inputs from the telephone company, to the CO Line inputs of the
system, and to Power Failure SLTs.
The diagram in Figure 3-44 shows the wiring for the first of six circuits wired consecutively on
the amphenol cable (It uses the first 4 pairs on the block. The next circuit uses the next 4 pairs,
etc.) The relay is a DPDT (Dual Pole Dual Throw). There are a total of 6 relays on the PFTU.
When the power is ON, the relay connects COR1-IN to COR1-OUT and COT1-IN to COR1-OUT.
When the power is OFF, the relay switches so that the relay now connects COR1-IN to TEL1-R
and COT1-IN to TEL1-T.
The basic connections of circuit 1 are shown in Figure 3-44 and the total connector
configuration is given in Table 3-23. Note that the SLT may also be connected to a SLIB as
shown in the figure.
Figure 3-44: PFTU Wiring Example (Circuit 1)
The SLIBE Subscriber (SLIB1-R and SLIB1-T) is only a connection so that the SLTs
can also be used off the SLIB card. There is no relay connection involved with this
pair. It is always connected to the SLIB card. When the power is ON, the relay is not
connected to the SLIBs. When the power is OFF, the KSU SLIB is not powered up and
the SLTs are now connected to the CO lines.
MDF (PFTU)
COR1-IN
COT1-IN
COR1-OUT
COT1-OUT
TEL1-R
TEL1-T
SLIB1-R
SLIB1-T
CO LINE
LCOBC
SLT
SLIBE
Subscriber
OR/WH
WH/BL
BL/WH
BN/WH
WH/BN
WH/GN
GN/WH
WH/OR