Systran SCRAMNet+ VME3U, Hardware Reference Manual

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OPERATION
Copyright 1995, S
YS
I
RAN
Corp. 4-24 VME3U H/W REFERENCE
Figure 4-8 Fiber Optic Loopback Mode
The optional Fiber Optic Bypass switch must be installed for this to work. However, in
the absence of the Fiber Optic Bypass switch, fiber optic cables could be run from the
node s transmitter output connectors to the receiver input connectors. This configuration,
with Insert Node enabled, would constitute a fiber optic loopback mode for stand-alone
testing. Disable Fiber Optic Loopback (CSR2, bit 6) must be set ON when the node is in
use as a part of the network. However, this configuration could not be used in a network
ring in the place of a Fiber Optic Bypass Switch because it would cause a break in ring
continuity.
4.10.4 Node Insert Mode
In this mode the node becomes part of the network (Figure 4-9).
Table 4-11 Node Insert Mode
State Register Setting
Receive Enable CSR0, bit 0 ON
Transmit Enable CSR0, bit 1 ON
Insert Node CSR0, bit 15 ON
Enable Wire Loopback CSR2, bit 7 OFF
Disable Fiber Optic Loopback CSR2, bit 6 ON
Mechanical Switch Override CSR8, bit 11 ON
F
NOTE: A node in Wire Loopback mode and Insert Node will create a break in the
network ring which will disable all nodes. The Wire Loopback and Fiber Optic
Loopback and/or Mechanical Switch loopback modes should not be enabled
simultaneously.