East Coast Datacom Nx8- Dual Composite MUX High-Speed 16-Port TDM..., Operation Manual

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3.3.1 Processor Card Replacement
The processor card may be replaced with power applied to the system, but it is
recommended that the process of removal and insertion be carried out with
AC power OFF .
There is no information preserved by keeping the AC power on the system while the
processor card is replaced.
The processor card may be removed by unlocking the plug-in via the two front panel locking
screws, and pulling on the U-shaped card pull mounted on the front panel.
Upon replacement of the processor card the user should insure that the card edges are
aligned with and inserted into the card guides on either side of the processor card slot
position in the main chassis. Once aligned in this way, the processor card may be pushed
completely into the main chassis. The processor card must then be securely fastened in
place by tightening the two front panel locking screws.
3.4 Port I/O Cards
The port I/O cards (4 per system) comprise the circuits that provide electrical conversion
between the channel ports and the multiplexer logic, and perform some of the data formatting
(e.g., Sync-Async conversion).
3.4.1 Port I/O Card Replacement
The port I/O cards are designed to be hot-swappable. While power is applied and the Nx8-
DualMUX system is operational, the user may remove and replace a port I/O card without
disruption to the normal flow of data across other active channels and the composite port.
After replacement, the system will re-program the new port I/O card according to the working
configuration stored in RAM on the processor card.
The port I/O card may be removed by unlocking the plug-in via the two front panel locking
screws, and pulling on the U-shaped card pull mounted on the front panel.
Upon replacement of the port I/O card the user should insure that the card edges are aligned
with and inserted into the card guides on either side of the port I/O card slot position in the
main chassis. Once aligned in this way, the port I/O card may be pushed completely into the
main chassis. The processor card must then be securely fastened in place by tightening the
two front panel locking screws.
3.5 Troubleshooting
The intent of troubleshooting the Nx8-DualMUX is to isolate a problem and determine if it
may be resolved through the replacement of a system module or cable rather than the entire
system.
3.5.1 Basic System Checks and Operation
The decision tree of Figure 12 illustrates the steps to determine the corrective action for a
basic system fault. Most problems of this nature can be resolved by exchange of one of the
replaceable plug in sub-assemblies. In rare instances, the system may need to be returned to
the factory for repair.