Line Module Power Converter; Ring Multiplexer; Ring Bus; Lm And Rlm Ringing Process - Nortel DMS-100 Series General Description Manual

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The RGI card also monitors ring generator output levels and reports any
problems to the line module controller (LMC) through the signaling processor
(SP).

Line module power converter

The ring generator is actually part of a LM/RLM power converter. The power
converter supplies both a regulated +24V for use in the LM/RLM shelf and a
programmable ac/dc voltage. The programmable source is capable of
producing ac or dc outputs at a wide range of voltages and frequencies. The
programmable source is the ring generator portion of the power converter.
The ringing generator receives a pulse-width modulated drive signal from the
RGI. The drive signal drives a 4-transistor balanced-bridge amplifier that
drives the ringing bus in the LM/RLM shelf. The amplifier bridge is balanced
for a drive signal of 50 percent duty cycle (50 percent on, 50 percent off)
results in zero output.
Output voltage magnitude, polarity, and frequency are controlled by the duty
cycle and frequency of the drive signal from the RGI.

Ring multiplexer

The ring MUX multiplexes the outputs of the ring generators onto the line
drawer internal ring bus. Each line drawer has a ring MUX
(NT2X20/NT2X02). The ring MUX receives messages from the LM/RLM
controller through the signal processor instructing it to connect the line drawer
internal ring bus to the appropriate ring generator.

Ring bus

The ring bus brings the ringing signal to all of the line cards in the line drawer.
A ringing relay on each line card attaches and detaches the subscriber tip or
ring lead to the ringing bus under the control of the LM/RLM controller so that
ringing voltages can be applied.

LM and RLM ringing process

The LM and RLM contain several processors that carry out call processing
tasks under the direction of the DMS-100 central control (CC). The following
describes the processors associated with ringing and the tasks they perform in
the ringing process.
synchromonic MF - NT2X27AE
20 Hz BOC coded ringing (105 V RMS) - NT2X27AF
DMS-100 Family DMS-100 Ringing System BASE15 and up
Ringing in Series I peripherals 2-3