Handbook for Sound Engineers

Message Repeaters and Evacuation Systems 1517

A message repeater can also be connected to
controlled doors such as in geriatric and psychiatric
wards to tell nurses of unauthorized door openings.
Voice messages can announce immediately throughout
the building which door is open, so personnel do not
have to go to a central alarm panel to see which door is
ajar, a much more effective and faster method than
visual indications.
When a Code Blue Dispatch happens, message
repeaters can instantaneously repeat the message as
often as required without requiring dedicated personnel.

40.4.2 Factory Floor Applications for Message
Repeaters

Just-in-time manufacturing is a very popular way for
companies to cut expenses. Some companies have docu-
mented savings of over one million dollars annually in
reduced inventory expenses by having components
delivered where required just-in-time. This way, unused
parts don’t require valuable and expensive floor space,
nor does the production line ever slow due to lack of
components. Many of the largest factories in the
country, such as Motorola, General Motors, and Xerox,
have been practicing this method of cost reduction for
many years.

Message repeaters can be used to broadcast a

message when certain parts need to be restocked.

Messages can be triggered manually by having the

assembly operator push a button, or automatically with

a sensor to trip the message when the weight of the bin

containing components becomes too light, sending a

verbal message to stock.

Repeaters can also be used to announce lunch time,

scheduled breaks, safety reminders, company announce-

ments, and so forth. They can be configured to know

when someone is entering (versus exiting) a hard hat

area. A warning message can be announced on entering.

A message reminding visitors to return their hard hats

and protective eyewear can also be announced on

exiting the area.

Another interesting use of a message repeater is the

elimination of acoustical feedback in noisy environ-

ments. By recording the message or page on a message

repeater and playing it back as soon as the recording is

finished, the microphone-amplifier-loudspeaker-room

feedback loop is broken and feedback is eliminated and

pages can be automatically repeated. With PageDelay™

from ALARMCO, pages can be monitored as they are

being recorded. Inappropriate pages can easily be

canceled before they are aired.

40.4.3 Retail Store Applications for Message

Repeaters

Message repeaters are ideal for in-store assistance

requests. In-store assistance is becoming increasingly

popular with retailers because it allows them to cut the

expense of large staffs while still delivering service to

customers who need it. Often the signs asking

customers to “Press the button for assistance in this

department” is connected to a message repeater.

Figure 40-2. An intelligent message repeater. Courtesy ALARMCO.

A/D, D/A

conversion circuitry

Filtering

Telephone

network

interface

Aux Mircophone Music feedthrough Control phone

(Audio inputs)

Audio outputs

Microprocessor

Control circuitry

User program storage

Internal program storage

Digitized message storage

Command prompt

audio storage

Contact closure

control inputs

Form C output relays

Serial communications link