Rs422 And Fiber Interface; And Fiber Interface - GE C30 Instruction Manual

CHAPTER 3: INSTALLATION
3.4.5.4 Receive timing
The RS422 interface utilizes NRZI-MARK modulation code and therefore does not rely on an Rx clock to recapture data.
NRZI-MARK is an edge-type, invertible, self-clocking code.
To recover the Rx clock from the data-stream, an integrated digital phase lock loop (DPLL) circuit is utilized. The DPLL is
driven by an internal clock, which is 16-times over-sampled, and uses this clock along with the data-stream to generate a
data clock that can be used as the serial communication controller (SCC) receive clock.

3.4.6 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.
When using a laser interface, attenuators can be necessary to ensure that you do not exceed
maximum optical input power to the receiver.
The connections shown in the figure are for multiplexers configured as data communications equipment (DCE) units.
3.4.7 G.703 and fiber interface
The following figure shows the combined G.703 plus fiberoptic interface configuration at 64 kbps. The 7E, 7F, 7G, 7Q, and
75 modules are used in configurations where channel 1 is employed via the G.703 interface (possibly with a multiplexer)
and channel 2 via direct fiber. AWG 24 twisted shielded pair is recommended for external G.703 connections connecting
the shield to pin 1a at one end only. For the direct fiber channel, address power budget issues properly. See previous
sections for details on the G.703 and fiber interfaces.
When using a laser interface, attenuators can be necessary to ensure that you do not exceed the
maximum optical input power to the receiver.
C30 CONTROLLER SYSTEM – INSTRUCTION MANUAL
Figure 3-39: RS422 and fiber interface connection
DIRECT INPUT AND OUTPUT COMMUNICATIONS
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