Fire-Lite Alarms MS-9200 Programming, Installation, Maintenance And Operating Instruction Manual page 35

Wiring the Signaling Line Circuit
Style 7 Four-Wire Communications Loop (Supervised and Power-limited)
The 4-wire communications loop meets NFPA 72 Style 7 requirements. By flanking each communications loop
device with a pair of I300 Fault Isolator Modules, each device is protected from short circuit faults that may occur on
other devices. For example, a fault on Zone 02 will not affect Zones 01 and 03. The isolator modules on either side
of Zone 02 will open the loop. Zone 01 will still operate from power on Loop Out and Zone 03 will operate from
Loop Return. Since the MS-9200 will no longer be able to communicate with Zone 02, a trouble signal(s) will be
generated for that device. No T-tapping or branching is allowed on this circuit. The ratings and characteristics are the
same as for a 4-wire circuit meeting NFPA Style 6 requirements.
FIGURE 2-13:
Isolator Module
2
BG-10LX
4
I300
Isolator Module
CAUTION! Do not loop wiring under any termi-
nals. Break wire run to maintain supervision.
32
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4-Wire Communications Loop
I300
4
3
1
Protected Premises
Zone '01'
3
2 1
T
B
6
Connect Loop Out to TB6-3(+) and TB6-5 (-)
Connect Loop Return to TB6-4(+) and TB6-6(-)
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Protected Premises
Zone '02'
SD300
Protected Premises
Zone '03'
Shield
A B B+ A+ B- A-
1 2 3 4 5 6
Document #15668 Rev.I 04/20/98 P/N 15668:I
I300
Isolator Module
2
1
3 4
CP300
3 4
I300
Isolator Module
1 2
Note: Terminal designations are
shown for all I300 modules.