12(48)
Date
Rev
Documentnumber
Prepared
Doc respons/Approved
Checked
Reference
1999-07-15
A
1531-BDV BS 101 05 Uen
INSTALLATION INSTRUCTION
Subject responsible
6.5
Power failure circuit (PFC)
In the event of mains failure and if no battery back-up
is available for the PBX, there are normally 2 lines on
the BTU-A and BTU-C (see under BTU-C on next
page) board which automatically switch the trunk lines
to analogue telephones connected to this board.
On power failure, these telephones will automatically
be connected to the public exchange.
It is also possible to use the power failure telephones
during normal operation, if an ELU-A board is in-
stalled.
Indicator
BTC
BTU-A & BTU-C1
La
Lb
a
b
PFb
PFa
ELUA
Trunk
Power failure set
Relay shown in power fail position
6.4
BTU-A (ROF 157 5110/_) and
BTU-A2 (ROF 157 5120/_)
On delivery from the factory both contacts are in the OFF
position, and the line is a normal trunk.
When both contacts on a DIP-switch are set to position
ON, the line is to be regarded as a music source input.
Different contact positions are not allowed.
Note: Only lines 4 - 7 can be used as a music source
input. Not available on BTU-A subequipped ROF
157 5127/_.
.
85
86
87
88
The DIP-switch is shown
with both contacts in
OFF position
Line 4
Line 5
Line 6
Line 7
ON
1 2
26
28
30
32
C
18
20
22
24
A
LA0
Connection field 6
LA1
LB0
LB1
LA2
LA3
LB2
LB3
LA4
LA5
LB4
LB5
LA6
LA7
LB6
LB7
Line wires for
connection to
Public Exchange
*)
*)
Not available on sub-equipped board see below