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Document 15949 Rev. E 4/12/95 P/N 15949:E
Table 3-1: Communications Loop Performance
Fault Condition
Single
Open on
Loop
Single
Ground
on Loop
Loop has
Been
Shorted
Loop
Shorted
and
Opened
Loop
Shorted
and
Grounded
Loop
Opened
and
Grounded
Commun
Loss
with
Control
Panel
Non-Redundant (2-Wire) Loop Operation
Trouble
(Note 1)
Trouble
with
Alarm
Capability
(Note 2)
Trouble
Trouble
Trouble
Trouble
Trouble
Redundant (4-Wire) Loop Operation
Trouble
with
Alarm
Capability
Trouble
with
Alarm
Capability
Trouble
Trouble
Trouble
Trouble
with Alarm
Capability
Trouble
Isolated Redundant (4-Wire) Loop Operation (Note 3)
Trouble
with
Alarm
Capability
Trouble
with
Alarm
Capability
Trouble
with
Alarm
Capability
Trouble
Trouble
with Alarm
Capability
Trouble
with Alarm
Capability
Trouble
Notes:
1.
Trouble indicates that a trouble signal will be generated at the control
panel under the abnormal condition.
2.
Alarm capability indicates whether or not an alarm signal can be trans-
mitted to the control panel during the abnormal condition.
3.
Isolated redundant loop operation is a method of protecting, or isolat-
ing, entire physical zones of devices on the communications loop from
faults that occur within other areas of the loop.
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