Specifications

X723-300151 2-9 Issue 2

Warning: Care should be exercised to ensure that the terminal being

connected to the multiplexer local port shares a common earth with the

multiplexer, otherwise permanent damage may result.

2.2.9 Ringing Voltage Connections

When using any 2-wire loop disconnect subscriber interface card, an AC

ringing supply will be required.

The ringing voltage may be supplied by an internal ringing generator card

DT579, or from an external supply connected to a terminal block on the

rear of the equipment. If an internal ringer is used, this will require a -

48VDC supply even on a mains powered chassis. This supply is switched

and fused on the 3000 power supply unit O/P panel.

The ringing generator card supplies ringing voltage for up to ten

telephones of REN = 1. Ringing generators cannot be paralleled to

increase output drive, therefore the 3200 backplane is split into 4 sections

to allow more than one ringer to be fitted if required, e.g. chassis equipped

with more than 10 subscriber circuits. Links must be positioned correctly

to disconnect the sections otherwise damage to the ringing generators will

result.

In order to select which supply is used, links are positioned on the

backplane to select the supply for each section, hence up to four internal

ringing generators may be fitted each supplying an individual section.

Any external ringing supply must be battery backed. The ringer supply

terminal block connections are as follows:

RV - ringing voltage

RR - ringing return (common to all sections)

RS - ringer start

The ringing supply must be across RV and RR. The RR terminal must be

connected to the station battery 0V.

MUX

-48V

50-125v RMS

AC source

Figure 2-1 External Ringing Supply Connections