DH+/RIO OPTICAL COMMUNICATION MODULES USERS MANUAL
Copyright © 2003 by Phoenix Digital Corporation, All Rights Reserved.
1.3.3.5 DETECT AND LOCATE NETWORK FAILURES
Fiber optic network fault conditions are reported by 1771, 1746, and 1756 Plug-In fiber optic
modules on diagnostic status bits 0 and 2... for fiber optic receive Channels A and B respectively
(see Figures 9 and 10). Fault conditions are reported by standalone, panelmount fiber optic mod-
ules on reed relay contact outputs on J4 connector pin #s 1,2 and 5,6... for fiber optic Channels A
and B respectively. (Diagnostic Select Switch SW4-1 must be set ON (active) to enable diagnostic
relay outputs.) If a fiber optic module detects a communication failure on the fiber optic receive data
inputs on either Channel A or B (due to either a media failure or failure of an adjacent fiber module)
it will assert the corresonding diagnostic status bit or contact output. These bits and contact outputs
may be used to locate the precise fiber where the failure is occurring.
1.3.3.6 TRAP-AND-HOLD, and LOCATE INTERMITTENT NETWORK FAILURES
When a fiber optic communication failure occurs it normally causes the network to remain in a
failed condition until the source of the failure is identified and corrected (solid failure). Con-
tact Outputs on standalone, panelmount fiber optic modules, and Diagnostic Status Bits on
1771, 1746, and 1756 plug-in fiber optic modules enable network maintenance personnel to
quickly locate this type of failure. However, occasionally an intermittent communication fail-
ure may occur, causing the network to briefly fail and then automatically recover. This type of
failure can be very difficult to locate because it does not remain in the failed condition long
enough for maintenance personnel to locate the source of the problem.
In the factory default configuration, all Phoenix Digital fiber optic communication modules provide
automatic recovery from communication failures. In the Auto-Recovery Mode of operation fiber
optic modules automatically detect, isolate, and correct communication failures by switching net-
work data around points of failure, and then automatically restore the network to its original configu-
ration when the sources of the failures are corrected. However, as an alternative to Auto-Recovery
Mode, Phoenix Digital’s fiber optic modules can also be configured for Trap Mode Operation. This
configuration may be selected on Standalone, Panelmount OCM Modules through Diagnostic Select
Switch 4 (see Table 9); on 1771 Plug-In OCM Modules through Diagnostic Select Switch 4 (see
Table 9) and/or the Diagnostic Control Byte (see Figure 9); on 1746 Plug-In OLC Modules through
the Diagnostic Select Switch 2 (see Table 11) and/or the Diagnostic Control Byte (see Figure 9); and
on 1756 Plug-In OCX Modules through Diagnostic Select Switch 2 (see Table 11).
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