GE N60 Instruction Manual page 83

CHAPTER 3: INSTALLATION
• IEEE standard — C37.94 for 1 × 128 kbps optical fiber interface (for 2G and 2H modules) or C37.94 for 2 × 64 kbps
optical fiber interface (for 76 and 77 modules)
• Fiber optic cable type — 50 nm or 62.5 μm core diameter optical fiber
• Fiber optic mode — multimode
• Fiber optic cable length — up to 2 km
• Fiber optic connector — type ST
• Wavelength — 820 ±40 nm
• Connection — as per all fiber optic connections, a Tx to Rx connection is required
The UR-series C37.94 communication module can be connected directly to any compliant digital multiplexer that supports
the IEEE C37.94 standard. The figure shows the concept.
Figure 3-43: IEEE C37.94 connection to compliant digital multiplexer
The UR-series C37.94 communication module can be connected to the electrical interface (G.703, RS422, or X.21) of a non-
compliant digital multiplexer via an optical-to-electrical interface converter that supports the IEEE C37.94 standard. The
following figure shows the concept.
Figure 3-44: IEEE C37.94 connection to non-compliant digital multiplexer
In 2008, GE Grid Solutions released revised modules 76 and 77 for C37.94 communication to enable multi-ended fault
location functionality with firmware 5.60 release and higher. All modules 76 and 77 shipped since the change support this
feature and are fully backward compatible with firmware releases below 5.60. For customers using firmware release 5.60
and higher, the module can be identified with "Rev D" printed on the module and is to be used on all ends of N60
communication for two and three terminal applications. Failure to use it at all ends results in intermittent communication
alarms. For customers using firmware revisions below 5.60, it is not required to match the revision of the modules installed.
The UR-series C37.94 communication module has six switches to set the clock configuration. The following figure shows
the functions of these control switches.
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
DIRECT INPUT AND OUTPUT COMMUNICATIONS
Figure 3-45: Switches
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