Specifications

Reference Guide
3-11
System Installation Ringing Generators
3.5.1 Ringing Generators (8906/890620)
Ringing generators are needed if the system has FXS or FXS-C cards, or if it has FXO or
FXO-C cards with ports connected to Manual Ringdown (MRD) circuits. The 20 Hz ringing
voltage may be provided either by an external source or with a Ringing Generator, which
requires the presence of -48 VDC in the system.
Ringing Generators cannot be used in
conjunction with external ringing sources.
The ringing generators provide a ringing voltage of 105 VAC at 20 Hz for 11 simultaneously
ringing voice ports. Since most systems will not have that much activity, a single Ringing
Generator might provide all of the power necessary to run the system. In a group where
incoming calls are at a minimum, 30 to 50 stations could share the same ringing generator.
Small groups with heavy incoming call volumes might require two or more Ringing
Generators. This condition should alert you to the need for additional equipment.
CAUTION!
Do not mix 8906 and 890620 Ringing Generators in the same chassis.
The compatibility of power sources used together are summarized in the system specification
section in this manual.
3.5.2 Installing the 105V Ringing Generator (8906/890620)
To install a 105V Ringing Generator, proceed as follows:
8.
Make sure power is turned off before inserting the ringing generator (8906 only).
The 890620 may be installed with power applied (“Hot swapping”).
The 890620 ring
generator has improved operating efficiency resulting in lower operating temperatures
which promote a longer life expectancy and support of more analog voice ports per ring
generator. It also provides inrush current control during start-up allowing for hot insertion
(plugging) without disrupting the integrated access system power supply busses.
9. Make sure jumper W201 is installed if this is the only ringing generator in the unit, or if
it is the MASTER ringing generator, Figure 3-7. If this is a SLAVE ringing generator, cut
jumper W201 with wire cutters.
10. For a two-sided chassis, remove the panel covering the rear power slots. You can insert
the generator into any of the five rear slots. For the front-loading chassis with power
supplies on top, remove the panel covering the front power slots, and insert the module in
any of the five slots. For the front-loading chassis with power supplies on the side, insert
the ringing generator only into slot R1.