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CHAPTER 5: Operation
5.2 Operating Procedure
CAUTION!
The protective-ground terminals of the multiplexor must be connected to
the protective-ground conductor of the power cord. The mux’s power-
cord plug should be inserted only in (a) an outlet provided with a
protective-ground contact or (b) an extension cord with a protective-
ground conductor; any type of power connection that doesn’t provide
grounding leaves the mux defenseless.
1. Plug the multiplexor’s AC power cord into an AC outlet. The Power
LED will light up to indicate that the mux is ON. If the local and
remote muxes are both operating and their main channels are properly
connected with fiberoptic cable, no other LED should be ON. If other
LEDs light up, please refer to
Chapter 6
.
2. To turn off the mux, simply remove its power cord from the outlet.
5.3 System Tests
The multiplexor performs two system tests: local loopback and remote
loopback.
5.3.1 L
OCAL
L
OOPBACK
When the mux performs local loopback, the data from the local transmitter
is looped back to the local receiver at the digital level, which checks all local
digital circuitry for proper operation.
To activate the local loopback test, press the “LLB” pushbutton located
on the front panel of the multiplexor (see Figure 5-1). If the local unit is
operating properly, the yellow Test LED should be lit and all other LEDs
should be off.
Furthermore, if the local and remote units are properly connected across
their main channels, the yellow Test LED on the remote unit should be lit
too, which indicates that a check of the local transmitter’s analog interface
and both the analog and digital remote receiver’s sections is being
performed.
Summary of Contents for MX880A
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