Federal Signal Corporation CommCenter D1 Series Manual

Model 300MB-SD
CommCenter Series D1
2561078I
Rev I3 0423
Printed in U.S.A.
Installation and Maintenance Manual

Limited Warranty
This product is subject to and covered by a limited warranty, a copy of which can be found at
www.fedsig.com/SSG-Warranty.A copy of this limited warranty can also be obtained by written
request to Federal Signal Corporation, 2645 Federal Signal Drive, University Park, IL 60484,
email to [email protected] or call [phone].
This limited warranty is in lieu of all other warranties, express or implied, contractual or statutory,
including, but not limited to the warranty of merchantability, warranty of tness for a particular
purpose and any warranty against failure of its essential purpose.
2645 Federal Signal Drive
University Park, Illinois 60484
www.fedsig.com
Customer Support 800-548-7229 • [phone]
Technical Support 800-524-3021 • [phone]
© Copyright 2013-2023 Federal Signal Corporation
All product names or trademarks are properties of their respective owners.

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Installation and Maintenance Manual
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Table of Contents
Safety Message to Installers of Federal Signal Products............................................................5
Unpacking the Product...................................................................................................................6
An Overview of the Model 300MB..................................................................................................6
Chassis Description............................................................................................................... 8
Input Conguration................................................................................................................. 8
Control Circuitry..................................................................................................................... 9
Power Requirements ............................................................................................................. 9
Recommendation for the Signal Lines........................................................................................12
Connecting Signal Lines...................................................................................................... 12
Connecting to Remote Devices....................................................................................................13
Balanced Line Application.................................................................................................... 13
Unbalanced Line Application................................................................................................ 14
Connecting a Low-Level Audio Input ................................................................................... 14
Connecting a Low-Level Audio Output................................................................................. 15
Typical Installations of the 300MB...............................................................................................16
As a SelecTone Control Center............................................................................................ 16
As a Remote Microphone and Message Playback.............................................................. 16
Driving a 25 VRMS Speaker Line ........................................................................................... 17
Interfacing with a Central Amplied System......................................................................... 18
As a Typical Central Power System..................................................................................... 18
Connecting Power to the CommCenter System.........................................................................19
For 120 Vac Operation......................................................................................................... 19
For 240 Vac Operation......................................................................................................... 19
For 24 Vdc Operation........................................................................................................... 19
Safety Messages to Maintenance Personnel..............................................................................20
Installing Storage Chips ...............................................................................................................21
Getting Replacement Parts...........................................................................................................23
Getting Service..............................................................................................................................23

44 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Figures
Figure 1 Dimensions and mounting holes...................................................................................7
Figure 2 Connections on the back of Model 300MB ................................................................. 13
Figure 3 Model AM25CK connections (balanced line)..............................................................13
Figure 4 Model 300CK connections (unbalanced line).............................................................14
Figure 5 Cascading multiple units..............................................................................................15
Figure 6 CommCenter as a SelecTone control center ..............................................................16
Figure 7 Model 300MB with remote microphone and message playback...............................17
Figure 8 Model 300MB with 25 VRMS connections...................................................................... 17
Figure 9 Model 300MB with central amplier connections ...................................................... 18
Figure 10 Typical central power system..................................................................................... 18
Figure 11 Model 300MB motherboard......................................................................................... 22
Tables
Table 1 Kit contents........................................................................................................................ 6
Table 2 Model 300MB Series D motherboard............................................................................... 8
Table 3 Product specications.................................................................................................... 10
Table 4 Replacement parts.......................................................................................................... 23

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Installation and Maintenance Manual
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Safety Message to Installers of Federal Signal Products
Safety Message to Installers of Federal Signal Products
People’s lives depend on your proper installation and servicing of Federal Signal
products. It is important to read and follow all instructions shipped with this product.
Listed below are some other important safety instructions and precautions you should
follow:
• This device is to be installed by a trained electrician who is thoroughly familiar
with the National Electric Code and will follow the NEC guidelines as well as local
codes.
• The selection of the mounting location for the device, its controls, and routing of
the wiring is to be accomplished under the direction of the Facilities Engineer and
the Safety Engineer.
• Read and understand all instructions before installing or operating this equipment.
• Do not connect this unit to the system when power is on.
• Optimum sound distribution will be severely reduced if any objects are in front of
the speaker. Ensure that the front of the speaker is clear of any obstructions.
• All eective warning speakers produce loud sounds that may cause, in certain
situations, permanent hearing loss. Take appropriate precautions such as wearing
hearing protection.
• All eective warning speakers produce loud sounds that may cause, in certain
situations, permanent hearing loss. The device should be installed far enough
away from potential listeners to limit their exposure while still maintaining its
eectiveness. The OSHA Code of Federal Regulations 1910.95 Noise Standard
provides guidelines, which may be used regarding permissible noise exposure
levels.
• After installation, test the sound system to ensure proper operation.
• Show these instructions to your Safety Engineer and all operating personnel,
and then file them in a safe place and refer to them when maintaining and/or
reinstalling the unit.
• Establish a procedure to routinely check the sound system for proper activation
and operation.
Failure to follow all safety precautions and instructions may result in property damage,
serious injury, or death.

66 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Unpacking the Product
Unpacking the Product
After unpacking the product, examine it for damage that may have occurred in transit.
If the 300MB has been damaged, do not attempt to install or operate it. File a claim
immediately with the carrier, stating the extent of the damage. Carefully check all
envelopes, shipping labels, and tags before removing or discarding them. If any parts are
missing, please call Federal Signal Customer Support at 708-534-4756 or 877-289-3246.
Table 1 Kit contents
Qty. Description Part Number
1 Plug, 10-Position 140332-10
1 Plug, 17-Position 140332-17
An Overview of the Model 300MB
The CommCenter, Model 300MB Series D1 is a digital playback device that is
capable of generating up to six dierent prerecorded voice messages, melodies,
tones, and/or signals. This central control device interfaces with any decentralized
or centrally amplified system. The CommCenter can control signal lines to Federal
Signal SelecTone®Models 300GC, 300GCX, 300X, 302GC, 302GCX, 302X, and
50GC speaker/amplifiers. It can also interface with any SelecTone Control Unit,
Models 300VSC or 300SCW-1. It can directly drive speakers designed for 25 VRMS
line operation. It can also provide a 1 VP-P audio signal and can be used as a remote
audio input for a public address sound system. Using the cascading function, 300MB
CommCenters can be linked together to provide a system with the capability of more
than six messages.
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.
IMPORTANT: The Series D CommCenters use a dierent storage IC than the Series
A, Series B, and Series C. These ICs cannot be interchanged between Series A,
Series, B, and Series C models. Be sure to verify which series CommCenter you have
before ordering any additional messages.
The CommCenter is intended to be installed only in indoor (NEMA 1) or other
protected installations. It can be mounted on any horizontal or vertical surface
using #10 screws appropriate for the type of mounting surface material and the four
mounting holes in the housing. See Figure 1.

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Installation and Maintenance Manual
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An Overview of the Model 300MB
Figure 1 Dimensions and mounting holes
3
4
1
2
KNOCKOUT PROVISION
0.87 in (2.21 cm) DIA., 5 PLACES
290A7328
FIELD WIRING BLOCK FOR
120/240 V POWER CONNECTION
2.27 in
(5.77 cm)
1.06 in
(2.70 cm)
1.08 in
(2.74 cm)
2.86 in
(7.26 cm)
3.57 in
(9.07 cm)
9.41 in
(23.90 cm)
6.77 in
(17.20 cm)
1.18 in
(3.00 cm)
2.20 in
(5.59 cm)
1.28 in
(3.25 cm) 11.57 in
(29.40 cm)
2.15 in
(5.46 cm)
6.87 in
(17.45 cm)
9.75 in
(24.77 cm)
COVER REMOVED TO SHOW FOUR MOUNTING HOLES 0.20 in (51 cm) DIA., FOR #10 SCREWS
The CommCenter can be used for a variety of prioritized signaling purposes, such
as indicating the status of a machine or process, background messages, evacuation,
alarm, start and dismissal, and other audible notification applications. The system
can be automated if external (customer-supplied) devices such as programmable
controllers, heat detectors, switches, or program clocks are connected to the remote
inputs. This product is not listed for fire use.
A CommCenter plays and amplifies messages through signal lines to the remote
SelecTone®devices in the system. To connect the SelecTone speaker/amplifier to the
signal line, a Model AM25CK Connector Kit is required in each SelecTone device.
Speakers designed for 25-volt operation can connect directly to the 25-volt output.
Each message can be activated by a contact closure or opening at its associated
remote control input. The remote control inputs can be configured to work with either
latching or momentary contacts.
Each CommCenter can accommodate up to six storage chips, selected from a
library of prerecorded voice messages, melodies, tones, and/or signals. There is one
message per storage chip. Each chip plugs into a 28-pin IC socket. The six sockets
are labeled PRIORITY TONE 1 through PRIORITY TONE 6.See Figure 11 on
page 22.

88 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
An Overview of the Model 300MB
Chassis Description
The CommCenter is assembled in a black, powder-coated, steel, two-piece housing.
The cover is attached to the housing with four screws, two along each long edge of
the enclosure. The rear of the housing incorporates two field-wiring compartments
baed o from the printed circuit board area. One compartment is for the connection
of the Class II power and signal lines, and the other is for the connection of the ClassI
power lines. These areas are provided with knockouts to allow the external wiring to
enter the unit through appropriate installer-supplied bushings.
Input Conguration
The CommCenter can be configured for remote activation in four ways:
• Normally open latching contacts
• Normally open momentary contacts
• Normally closed latching contacts
• Normally closed momentary contacts
The CommCenter is factory-set to be activated by closing a normally open latching
contact between the associated input and circuit ground. When activated, the
message continues to loop and repeat. It stops as soon as it is deactivated. When
configured for momentary activation, the message continues to loop and repeat until
the input is deactivated. When the input is deactivated, it plays the entire message
before stopping.
Each of the six inputs can be configured individually by moving a two-position jumper
on a three-position header. See Table 2 for a list of the priority tones, their associated
jumper designations, and their silkscreened label printed circuit board.
Table 2 Model 300MB Series D motherboard
MESSAGE JUMPER MARKING JUMPER MARKING
PRIORITY
TONE1 J9 NO NC J12 R M
PRIORITY
TONE 2 J10 NO NC J14 R M
PRIORITY
TONE 3 J11 NO NC J13 R M
PRIORITY
TONE 4 J5 NO NC J8 R M
PRIORITY
TONE 5 J4 NO NC J7 R M
PRIORITY
TONE 6 J3 NO NC J6 R M
NOTES:
NO NC congures an individual channel to interface
to normally open (NO) or normally closed (NC)
contacts.
R M congures an individual channel to interface to
a latched contact (R) or a momentary contact (M).

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Installation and Maintenance Manual
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An Overview of the Model 300MB
Control Circuitry
The control circuitry in the CommCenter has a built-in priority level feature. If a
message is already sounding when a higher priority message is activated, the higher
priority message automatically overrides the lower priority message. When the higher
priority message is deactivated, the lower priority message is initiated as long as it
is still activated. The messages are prioritized with Priority Tone 1 having the highest
priority down to Priority Tone 6. The cascade input has the lowest level of priority.
A message can be activated from the tone activation inputs on TB1. For example, a
dry contact, either normally open or normally closed (depending on the configuration)
will activate a tone when it is connected between the associated message (TB1-1
through TB1-6) and COM (TB1-7). The configuration of these channels is described in
"Input Configuration" on page 8. These inputs are opto-coupled to reduce the
possibility of noise on the signal lines falsely activating a message.
There are two sets of contacts that can be used to monitor the status of a
CommCenter. When power is applied, a relay with form C contacts is activated. These
contacts are connected to TB2 and are labeled Power Monitor Relay. The second set
of contacts monitor activation of any of the six messages or a cascaded input. These
contacts are labeled Push-to-Talk (PTT) Relay on TB1.
Power Requirements
SHOCK HAZARD: Do not perform any installation or maintenance on this
system when power is on. Because the 300MB does not have a power switch,
ensure that the power is disconnected before proceeding. Failure to heed this
warning may cause serious injury or death.
The Model 300MB can be operated on 120 Vac, 240 Vac, or 24 Vdc input power. To
prevent power to the CommCenter from being accidently turned o, the unit does not
have a power switch.

1010 Model 300MB-SD CommCenter Series D1
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An Overview of the Model 300MB
Table 3 Product specications
Power Input
Input Voltage 120/240 Vac, 50 Hz to 60 Hz; 24 Vdc
Standby Current 50 mA, 120 Vac
25 mA, 240 Vac
Operating Current 210 mA (max.)
Power Consumption 26 W (max.)
Emergency Power Source Input
Input Voltage 22 Vdc to 32 Vdc
Standby Current 90 mA
Operating Current 760 mA
Audio/Cascade Input
Input Impedance 5 k Ω
Input Voltage 1 VP-P (max.)
Audio Outputs
Output Impedance
Unbalanced Signal Line 25 Ω (max.)
Unbalanced Signal Line, Standby 120 Ω
Balanced Signal Line 40 Ω (max.)
Low-Level Signal Line 600 Ω
Output Voltage Levels, No Load (< 3% THD)
Unbalanced Signal Line 9 VRMS
Balanced Signal Line 17 VRMS
Low-Level Signal Line 1 VP-P
Output Voltage Levels, Max. Load (< 3% THD)
Unbalanced Signal Line 8 VRMS (25 Ω load)
Balanced Signal Line 15 VRMS (40 Ω load)
Low-Level Signal Line 1 VP-P (600 Ω load)
Tone Output Voltage Levels, No Load (sq. wave)
Unbalanced Signal Line 12 VRMS
Balanced Signal Line 25 VRMS
Low-Level Signal Line 1 VP-P
Tone Output Levels Max. Load (sq. wave)
Unbalanced Signal Line 12 VRMS (25 Ω load)
Balanced Signal Line 20 VRMS (40 Ω load)
Low-Level Signal Line 0.56 VRMS (600 Ω load)
Signal to Noise Ratio (< 1.5 % THD)
Chip Input 67 dBA

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Installation and Maintenance Manual
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An Overview of the Model 300MB
Table 3 Product specications (continued)
Audio Frequency Response, Balanced Signal Line
40 Ω Max. Load, from 250 Hz to 80 kHz
(Reference 1 kHz) -3 dB
40 Ω Max. Load, from 450 Hz to 60 kHz
(Reference 1 kHz) -1 dB
No Load, from 100 Hz to 90 kHz
(Reference 1 kHz) -3 dB
No Load, from 200 Hz to 60 kHz
(Reference 1 kHz) -1 dB
Audio Distortion from Cascade Input to Balanced Signal
Line Output (40 Ω Load) 0.2 %
Fuses
F1 Type GMC-1, 1 A, 250 V
F2 Type GMC-1/2, 1/2 A, 250 V
Physical Specications
Shipping Weight 6.6 lb (3.0 kg)
Net Weight 5.5 lb (2.5 kg)
Dimensions (D,W, H) 2.27 x 9.41 x 11.57 in
(57.7 x 239.0 x 293.9 mm)
Operating Temperature 32°F to 120°F (0°C to 49°C)

1212 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Recommendation for the Signal Lines
Recommendation for the Signal Lines
REDUCED SOUND OUTPUT: If too small a diameter cable is used, unacceptable
signal voltage drop in the signal line will cause reduced sound output from
the remote signal device. Only use a cable having wire diameter greater than
22 AWG.
The signal lines transfer tone signals and verbal messages from the CommCenter
to the remote SelecTone®devices. To reduce the possibility of cross talk, hum, and
static-noise pickup, the signal lines must be twisted-pair, shielded audio cable. In
the majority of systems, use AWG 18 twisted-pair audio cables. Federal Signal does
not recommend that new or existing telephone lines be used as signal lines in a
SelecTone system for the following reasons:
• Interference from other services or systems, or interference from the system to
other services
• Cross talk, interference, or hum induced by other telephone lines
• Extended downtime because of the second-party involvement required to service
the lines
• The additional cost of installation, interfacing devices, and monthly charges as
opposed to a one-time cost of performing the installation
Connecting Signal Lines
CROSSTALK INTERFERENCE: Mixing signal lines with power lines could
cause electrical interference, which could impede or render the system
inoperable.
SHOCK HAZARD: Do not install signal lines in the same conduit with power lines.
Avoid routing signal lines on cable trays with high voltage power lines.
To connect the signal lines of the SelecTone system to the 300MB, connect a color-
coded, twisted pair of audio cables with conductors no smaller than 18 AWG to
the TB1-13 and TB1-14 terminals on TB1. Before using TB1-13 and TB1-14, remove
the labeled jumper. Every remote SelecTone signaling device in the system can be
connected in parallel or series to these lines. See Figure 2.

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Installation and Maintenance Manual
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Connecting to Remote Devices
Figure 2 Connections on the back of Model 300MB
NOT USED NOT USED + 24VDC - 24VDC POWER DOWN NO NC COM ENABLE SIGNAL MIC OUT SIG COM SIG HI SIG SIG SIGNAL ENABLE COM NC NO COM MESSAGE 1 MESSAGE 2 MESSAGE 3 MESSAGE 4 MESSAGE 5 MESSAGE 6
290A7329
PTT RELAY
CASCADE IN CASCADE OUT
POWER MONITOR RELAY
25 VRMS LINE
GND
120/240 Vac
CLASS II FIELD WIRING
COMPARTMENT
CLASS I FIELD WIRING
COMPARTMENT
KNOCK-OUTS IN
REAR OF HOUSING
MODEL 300MB REAR VIEW
(BACK OF HOUSING IS REMOVED FOR CLARITY)
OUTPUT LEVEL
TB2 TB1
10 9 8 7 6 5 4 3 2 1 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
For non-SelecTone 25 VRMS speakers, such as ceiling speakers, connect the signal lines
directly to TB1-13 and TB1-14 of terminal block TB1. Before using TB1-13 and
TB1-14, remove the labeled jumper. Signal line losses must be considered when
calculating how many speakers can be connected to the 300MB.
Connecting to Remote Devices
Physically install the remote SelecTone device(s) following the instructions included
with the device.
Balanced Line Application
For 300GC, 300GCX, 300X, 302GC, 302GCX, 302X or 50GC speakers, an AM25CK
Connector Kit is required for connection to the balanced signal output of the 300MB.
The AM25CK properly terminates the balanced signal lines to the amplifier in the
300GC, 300GCX, 300X, 302GC, 302GCX, 302X and 50GC.
Remove the labeled jumper from terminals TB1-13 and TB1-14 of terminal block TB1.
Connect the white input wires on the AM25CK to the terminals TB1-13 and TB1-14 of
terminal block TB1 on the 300MB as shown in Figure 3. The AM25CK and AM70CK
Connector Kits are NOT polarity sensitive, but polarity must be observed when placing
speakers in close proximity to each other.
Figure 3 Model AM25CK connections (balanced line)
300GC
TERMINAL BLOCK (TB1)
ON REAR OF 300MB
AM25CK
300GC
AM25CK
14 13
290A7443
SHIELDED TWISTED PAIR
SIGNAL LINE TO ADDITIONAL
SELECTONES

1414 Model 300MB-SD CommCenter Series D1
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Connecting to Remote Devices
For 25 VRMS line-operated speakers, connect them directly to the balanced signal
output of the 300MB. Remove the labeled jumper from terminals TB1-13 and TB1-14 of
terminal block TB1. Connect the speakers in parallel to the terminals TB1-13 and TB1-14
of terminal block TB1 on the 300MB. Unlike the unbalanced line output, this output is
not switched.
IMPORTANT: This output is to be used only if there are no SelecTone®system devices
connected to the unbalanced signal output (across TB1-15 and TB1-16).
Unbalanced Line Application
For existing SelecTone systems using the 300CK Connector Kit, use the unbalanced
signal outputs on the 300MB. A 300CK Connect Kit is required to connect a 300GC,
300GCX, 300X, 302GC, 302GCX, 302X or 50GC to the unbalanced signal lines. The
300CK properly terminates the signal lines to the amplifier in the 300GC, 300GCX,
300X, 302GC, 302GCX, 302X and 50GC. Connect the blue wire on the 300CK to the
SIG COM wire from the 300MB. Connect the yellow wire on the 300CK to the SIG HI
wire from the 300MB. See Figure 4.
Figure 4 Model 300CK connections (unbalanced line)
290A7332
300GC
TERMINAL BLOCK (TB1)
ON REAR OF 300MB
YEL BLU YEL BLU
300CK
300GC
300CK
COM SIG
HI
16 15 SHIELDED TWISTED
PAIR SIGNAL LINE TO
ADDITIONAL SELECTONES
Connecting a Low-Level Audio Input
There is a provision for a low-level, low-impedance, audio signal input at the rear of the
300MB. It is designed to accept a cascaded input from a primary CommCenter (TB1-12)
But it also accepts audio from a telephone system, radio receiver, CD player, or tape
player. When the ENABLE pin (TB2-2) on the cascade input is pulled to circuit ground,
audio on the cascade-in signal line is gated through the CommCenter and output on
the signal lines. This input is the lowest priority. The audio-level input should be 1 VP-P.
When cascading units, connect the cascade-out ENABLE and SIGNAL terminals and the
ground of the secondary unit to the cascade-in ENABLE and SIGNAL terminals on the
primary unit. The SIG COM terminals (TB1-16) of both units also need to be connected
together as shown in Figure 5.

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Installation and Maintenance Manual
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Connecting to Remote Devices
Figure 5 Cascading multiple units
GROUND
PRIMARY
SECONDARY
SIGNAL
ENABLE
CASCADE
OUT
120/240 Vac
GROUND
290A7317
10 2 1 17161514 1
10 16 12 11 11
TB2 TB1
TB2
GAIN
CNTR
GAIN
CNTR
TB1
120 Vac 120 Vac 120 Vac
LOCAL PWR. LOCAL PWR.
POWER LINES
MODEL
300GC
MODEL 300MB
MODEL 300MB
MODEL
AM25CK
SIGNAL LINES SHIELDED
TWISTED PAIR
SIGNAL
ENABLE
CASCADE IN
120/240 Vac
13
Connecting a Low-Level Audio Output
The 300MB also has a 1 VP-P audio output that is designed to drive the cascaded input
of a secondary CommCenter. This low-level output is available across terminals TB1-16
and TB1-17. It can also be connected to an analog fiber optic transmitter so that audio
can be transmitted over a fiber-optic link in an electrically noisy environment.

1616 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Typical Installations of the 300MB
Typical Installations of the 300MB
This section describes four typical installations of the 300MB system.
As a SelecTone Control Center
In this installation, shown in Figure 6, the CommCenter is acting as a SelecTone®
control center driving a 25 VRMS signal line. Remote speaker/amplifiers have the signal
coupled in through an AM25CK.
Figure 6 CommCenter as a SelecTone control center
GROUND
290A7321
10 1 171615 1
TB2 TB1
GAIN
CNTR
MODEL 300GC
MODEL 300MB
MODEL AM25CK
SIGNAL LINES SHIELDED
TWISTED PAIR
120/240 Vac
120 Vac 120 Vac
LOCAL PWR. LOCAL PWR.
POWER LINES
1413
As a Remote Microphone and Message Playback
This installation uses a 300MB interface with a 300VSC-1 or 300SCW-1. The
CommCenter acts as a remote microphone audio input and adds message playback
capability to a SelecTone system. Adjust the gain on the 300MB so that the audio output
is at the required audio input level for the remote microphone input (16 mVRMS max.)
on the 300VSC-1 and the 300SCW-1. Failure to adjust the gain causes distortion and
clipping in the system. See Figure 7.

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Installation and Maintenance Manual
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Typical Installations of the 300MB
Figure 7 Model 300MB with remote microphone and message playback
GROUND
290A7517
10 1 17 16 10 8 1
TB2 TB1
GAIN
CNTR
4 5 1 7 12131417 16
TB1 TB2
MODEL 300GC
MODEL 300VCS-1
120 VCA
MODEL 300MB
MODEL AM25CK
SIGNAL LINES
SHIELDED
TWISTED PAIR
120/240 Vac
120 Vac 120 Vac 120 Vac
LOCAL
POWER
LOCAL
POWER
POWER
LINES
CONNECTIONS TO 300MC
TB1-8 PTT-NO
PTT-COM
SIG COM
MIC OUT
PTT
GND
MIC COM
MIC AUDIO IN
TB1-10
TB1-16
TB1-17
TB2-13
TB2-7
TB2-14
TB2-12
300MB
300VSC-1/300SCW-1
Driving a 25 VRMS Speaker Line
In this installation, the CommCenter is directly driving one or more speakers. The
total power consumed must not exceed the drive capability of the CommCenter. See
Figure 8.
Figure 8 Model 300MB with 25 VRMS connections
GROUND
290A7333
10 1 17 14 13 1
TB2 TB1
GAIN
CNTR
MODEL 300MB
SIGNAL LINES
SHIELDED
TWISTED PAIR
120/240 Vac TB1-13
TB1-14
SIGNAL -
SIGNAL +
TO ADDITIONAL SPEAKERS,
40 OHMS MAXIMUM LOAD

1818 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Typical Installations of the 300MB
Interfacing with a Central Amplied System
In this installation, the CommCenter is acting as an audio input to a central amplifier.
Message playback can be added to an existing centrally amplified paging system. See
Figure 9.
Figure 9 Model 300MB with central amplier connections
GROUND
290A7334
10 1 1716 1
TB2 TB1
GAIN
CNTR
MODEL 300MB
CENTRAL AMPLIFIER
SIGNAL LINES
SHIELDED
TWISTED PAIR
120/240 Vac TB1-16
TB1-17
SIGNAL COMMON
MICROPHONE OUT
TO ADDITIONAL SPEAKERS,
40 OHMS MAXIMUM LOAD
AUDIO INPUT
As a Typical Central Power System
In this installation a 24 Vdc power supply, such as a Model PS600, is driving the
CommCenter and one or more speakers. For additional information, including jumper
removal, see "For 24 Vdc Operation" on page 19. See Figure 10.
Figure 10 Typical central power system
290A7517
GROUND
10 8 7 115 1
TB2 TB1
GAIN
CNTR
MODEL 300GC
24 Vdc
MODEL 300MB
AM25CK
120/240 Vac NOT USED WITH THE MODEL PS600
24 Vdc
POWER SUPPLY
+
–
–SIGNAL LINES,
SHIELDED TWISTED PAIR
+
OUTPUT
POWER
LINES
1617

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Installation and Maintenance Manual
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Connecting Power to the CommCenter System
Connecting Power to the CommCenter System
QUALIFIED INSTALLERS ONLY: This device is to be installed by a trained
electrician who is thoroughly familiar with the National Electric Code and will
follow the NEC guidelines as well as local codes.
SHOCK HAZARD: Do not perform any installation or maintenance on this
system when power is on. Because the 300MB does not have a power switch,
ensure that the power is disconnected before proceeding. Failure to heed this
warning may cause serious injury or death.
CROSSTALK/INTERFERENCE HAZARD: Mixing power lines with signal lines
can cause cross talk, interference, or hum in the signal lines, which interferes
with the emergency warning capability of this equipment. Do not install power
lines in the same conduit as signal lines.
Operating power is connected to the 300MB through the three-position, field-wiring
terminal block located at the back of the unit. Two knockout openings are provided.
One knockout should be removed and provided with a bushing through which the
power lines can be routed into the field wiring compartment.
For 120 Vac Operation
The 300MB is factory-set for 120 Vac operation.
For 240 Vac Operation
Set switch SW1 on the motherboard to the 240 V position. See Figure 2 on page 13.
For 24 Vdc Operation
If using 24 Vdc either as a primary or auxiliary source of power, remove the labeled
jumper from terminals TB2-7 and TB2-8 of terminal block TB2 before using these
positions. Connect the "+" terminal of the 24 Vdc power supply to the terminal TB2-8
(+24Vdc) and "–" terminal of the 24 Vdc power supply to the terminal TB2-7 (-24 Vdc) of
the TB2 terminal block located in the back of the 300MB. Install a Class II power supply,
such as a Federal Signal PS600, and its associated wiring. See Figure 10 on page 18.

2020 Model 300MB-SD CommCenter Series D1
Federal Signal www.fedsig.com
Safety Messages to Maintenance Personnel
Safety Messages to Maintenance Personnel
This device is to be serviced by a trained electrician who is thoroughly familiar with
the National Electric Code and will follow the NEC guidelines as well as local codes.
This service information is for qualified personnel only. To avoid electric shock, do not
perform any servicing other than changing fuses unless qualified to do so. Refer all
servicing to qualified service personnel.
Listed below are some important safety instructions and precautions you should
follow:
• Read and understand all instructions before operating this system.
• Do not perform any maintenance on this system when power is on. Because the
300MB does not have a power switch, ensure that the power is disconnected
before proceeding.
• Read and understand all instructions before operating this system.
• Always ensure that the power to the 300MB is disconnected before removing the
metal cover.
• Do not connect this unit to the system when power is on.
• All eective warning speakers produce loud sounds that may cause, in certain
situations, permanent hearing loss. Take appropriate precautions such as wearing
hearing protection.
• After installation, test the sound system to ensure proper operation.
• Establish a procedure to routinely check the sound system for proper activation
and operation.
Failure to follow all safety precautions and instructions may result in property damage,
serious injury, or death.