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Chapter 5
Crosspoint Modules
Crosspoint Module General Description
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2
3
The crosspoint module plugs into the module interconnect backplane via a high-density,
high-speed connector. Switching is performed in a three-stage "make before break"
process that eliminates unnecessary signals on the MI, while continually providing the
output module reclocker IC a valid source so that the reclocker remains locked:
The crosspoint module is switched so that the previous and next sources are both active on
the output module reclocker input.
The output module reclocker is switched to the next source.
The crosspoint module switches off the previous source.
All settings for the crosspoint circuitry are reset on module insertion within one frame (per
sync present) of when the resource module detects card presence.
There are three system indicator LEDs on the front edge of the module:
The green LED labelled "POWER" is the power supply indicator. It shows that +24V is
present on the module.
The LED labelled "ACT CTRL" is the control system acknowledgment. The LED shows a
steady red when the module is being initialized, and then turns green when the FPGA
has configured and the control system is communicating with the module. It flashes
green if there is an alarm condition on this module.
The LED labelled "ACT XPT" is the active crosspoint indicator. It indicates which
crosspoint card is active in redundant configurations.
Along with these LEDs, there are power and ground test points accessible on the front
portion of the board for troubleshooting and verification.
Temperature sensing circuits are present on the crosspoint module, so that the internal
frame temperature can be monitored.
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