Figure 3-8. Model 300MB with Central Amplifier Connections.
remote mic audio input level (16mVrms MAX.) for
the 300VSC-1. Failure to adjust this level will cause
distortion and clipping in the system.
C.
300MB Driving a 25Vrms Speaker Line
(see figure 3-7).
In this installation the CommCenter is di-
rectly driving a speaker or speakers, the total power
consumed not exceeding the drive capability of a
CommCenter.
D.
300MB Interfacing with a Central Ampli-
fied System (see figure 3-8).
In this installation the CommCenter is
acting as an audio input to a Central Amplifier. Mes-
sage playback can be added to an existing Centrally
Amplified Paging System.
3-12.
STORAGE CHIP INSTALLATION.
NOTE
The CommCenter accepts messages stored
on ICs and pluggable circuit boards. Both are
referred to as message chips in this manual.
The messages stored on pluggable circuit
boards will operate on all Series B, Series C,
and Series D Models.
The Series D CommCenters use a different
storage IC than the Series A, Series B, and
Series C. These ICs cannot be interchanged be-
tween Series A, Series, B, and Series C models.
Make sure to specify which series CommCen-
ter you have before ordering any additional
messages.
It is necessary to perform the procedures in
this section ONLY if it is required to change
the priority of the storage chips or adding a
different message to the unit is required.
The 300MB can accommodate up to six storage
chips. The CommCenter should be shipped from the
factory with the storage chips installed. Each storage
chip is marked with the Model Number and other
information.
Failure to follow all safety precautions and
instructions may result in property damage
serious injury, or death to you or others.
Do not perform any installation or mainte-
nance on this system when power is on.
This device is to be installed by a trained elec-
trician who is thoroughly familiar with the
National Electrical Code and will follow the
NEC guidelines as well as local codes.
NOTE
The Storage Chips and the CommCenter’s
circuitry can be destroyed or damaged by
static discharge. Observe anti-static proce-
dures when installing or servicing a
CommCenter.
Storage Chips should be installed starting at
Priority Tone 1 and working downward. If, for ex-
ample, only four messages are required, have PT1
through PT4 sockets occupied and leave PT5 and PT6
open.
To remove a storage chip gently pry it out of its
socket. To install the storage chips insert them into
the desired sockets on the printed circuit board as
shown in figure 1-3. Ensure that the notch on the
edge of the new storage chip is facing in the same
direction as the old one (next to the resistors at the
edge of the board) and that all pins are properly in-
serted in the socket—not bent under.
Test the CommCenter after any maintenance
is performed.
3-7
GROUND
290A2664-22B
10
1
17 16
1
TB-2
TB-1
GAIN
CNTR
MODEL 300MB
CENTRAL AMPLIFIER
SIGNAL LINES
SHIELDED
TWISTED PAIR
120/240 VAC
TB1-16
TB1-17
SIGNAL COMMON
MIC. OUT
TO ADDITIONAL SPEAKERS, 40 OHMS MAXIMUM LOAD
AUDIO INPUT
