2.7
Connecting A Power Failure Station
The system provides a tip and ring pair connected to line 1 as an emergency power failure
circuit. This circuit is active during a commercial AC power failure if an external battery
assembly is not installed to provide battery back-up power to the system. Connect an industry
standard, single-line telephone, such as a model 2500, to a power failure pair and use it to
provide communications capability until the AC power to the system is restored.
NOTE: The system also provides one power failure connection with each add-on expansion
module.
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Power Failure Jack (pins 3 & 4)
(16-Line, 32-Station Base Unit)
Power Failure Terminals on
Station Connection Block
(4-Line, 8-Station and 8-Line, 16-Station Base Units)
DSU221
Typical Industry Standard
Non-electronic Telephone
(Power Failure Interface)
Typical Industry Standard
Non-electronic Telephone
(Power Failure Interface)
Pin 3 = Power Failure Tip
Pin 4 = Power Failure Ring
1 2 3 4 5 6
Making A Power Failure Connection
IMI66–132
DSU II Digital Telephone System
2 – 28 Installing The DSU II Digital Telephone System
Summary of Contents for DSU II
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