363-206-305
Power
Issue 3 June 2000
4-11
Ringing Generator Units (RGU)
4
The AUA413 and AUA423 RGUs are used in the
SLC
-2000 MSDT as well as the
DDM-2000 FiberReach narrowband shelf. The AUA413 provides 20-Hz negative-
superimposed ringing current to satisfy loop applications for 0 to 132 ohms and
AUA423 should be placed in an NBS where any channel units are used whose
range exceeds 132 ohms. (See Figure 4-8.) The AUA413 and AUA423 RGUs
receive an input voltage in the -42 to -60 V DC range from the power converter
unit (PCU) and supply a ringing voltage of 20 Hz, 80 or 100 V rms sine wave,
respectively, superimposed on the negative input voltage. Both can ring up to
three lines simultaneously. Each line may have a maximum load of the five ringer
equivalent numbers (RENs). The AUA423 RGU satisfies the ringing requirements
for the longer loop applications where the loop impedance exceeds 130 ohms.
Each of the faceplates contains an LED indicator (FAIL) and three test points
(-20HZ, -48V
, and
GND)
.
An output alarm monitor circuit on the RGU monitors the output ringing voltage for
an over- or under-voltage condition and activates a red fail LED when either
condition occurs. This circuit pack is protected from lightning and power surges by
the output surge protection circuit.
Figure 4-8. AUA413 and AUA423 Ringing Generator Units
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