3-30 G60 Generator Management Relay GE Multilin3.3 DIRECT I/O COMMUNICATIONS 3 HARDWARE33.3.8 IEEE C37.94 INTERFACEThe UR-series IEEE C37.94 communication modules (76 and 77) are designed to interface with IEEE C37.94 compliantdigital multiplexers and/or an IEEE C37.94 compliant interface converter for use with direct input/output applications forfirmware revisions 3.30 and higher. The IEEE C37.94 standard defines a point-to-point optical link for synchronous databetween a multiplexer and a teleprotection device. This data is typically 64 kbps, but the standard provides for speeds up to64n kbps, where n = 1, 2,Ö, 12. The UR-series C37.94 communication module is 64 kbps only with n fixed at 1. The frameis a valid International Telecommunications Union (ITU-T) recommended G.704 pattern from the standpoint of framing anddata rate. The frame is 256 bits and is repeated at a frame rate of 8000 Hz, with a resultant bit rate of 2048 kbps.The specifications for the module are as follows:IEEE standard: C37.94 for 1 × 64 kbps optical fiber interfaceFiber optic cable type: 50 mm or 62.5 mm core diameter optical fiberFiber optic mode: multi-modeFiber optic cable length: up to 2 kmFiber optic connector: type STWavelength: 830 ±40 nmConnection: 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 supportsthe IEEE C37.94 standard as shown below.The UR-series C37.94 communication module can be connected to the electrical interface (G.703, RS422, or X.21) of anon-compliant digital multiplexer via an optical-to-electrical interface converter that supports the IEEE C37.94 standard, asshown below.The UR-series C37.94 communication module has six (6) switches that are used to set the clock configuration. The func-tions of these control switches is shown below.UR seriesrelayDigitalMultiplexerIEEE C37.94compliantIEEE C37.94Fiber Interfaceup to 2 kmUR seriesrelayDigitalMultiplexerwith EIA-422InterfaceIEEE C37.94Fiber Interfaceup to 2 kmIEEE C37.94ConverterRS422InterfacetetextxttexttetextxttextxttextxttextxttextxttextxttextxttextxttextxttextONOFFONOFFInternal Timing Mode Loop Timed1 53 42 6 1 53 42 6Switch Internal Loop Timed1 ON OFF2 ON OFF3 OFF OFF4 OFF OFF5 OFF OFF6 OFF OFF
