Rs422 And Fiber Interface; Ieee C37.94 Interface - GE N60 Instruction Manual

DIRECT INPUT AND OUTPUT COMMUNICATIONS
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3.4.7 RS422 and fiber interface

The following figure shows the combined RS422 plus fiberoptic interface configuration at 64 K baud. The 7L, 7M, 7N, 7P,
and 74 modules are used in two-terminal with a redundant channel or three-terminal configurations where channel 1 is
employed via the RS422 interface (possibly with a multiplexer) and channel 2 via direct fiber.
AWG 20-24 twisted shielded pair is recommended for external RS422 connections and ground the shield only at one end.
For the direct fiber channel, address power budget issues properly.
The connections shown in the figure are for multiplexers configured as data communications equipment (DCE) units.

3.4.8 IEEE C37.94 interface

The UR-series IEEE C37.94 communication modules (module types 2G, 2H, 2I, 2J, 76, and 77) are designed to interface with
IEEE C37.94 compliant digital multiplexers or an IEEE C37.94 compliant interface converter for use with direct input and
output applications. The IEEE C37.94 standard defines a point-to-point optical link for synchronous data between a
multiplexer and a teleprotection device. This data is typically 64 kbps, but the standard provides for speeds up to 64n kbps,
where n = 1, 2,..., 12. The UR-series C37.94 communication modules are either 64 kbps (with n fixed at 1) for 128 kbps (with
n fixed at 2). The frame is a valid International Telecommunications Union (ITU-T) recommended G.704 pattern from the
standpoint of framing and data 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:
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Figure 3-41: Two-channel two-clock RS422 interface connections
When using a laser interface, attenuators can be necessary to ensure that you do not exceed
maximum optical input power to the receiver.
Figure 3-42: RS422 and fiber interface connection
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
CHAPTER 3: INSTALLATION