GAI-Tronics 491-204 User Manual

Pub. 42004-195E

GAI-TRONICS® CORPORATION

A HUBBELL COMPANY

Model 491-204

Mine Dial/Page Telephone

Confidentiality Notice

This manual is provided solely as an operational, installation, and maintenance guide and contains
sensitive business and technical information that is confidential and proprietary to GAI-Tronics. GAI­Tronics retains all intellectual property and other rights in or to the information contained herein, and
such information may only be used in connection with the operation of your GAI-Tronics product or
system. This manual may not be disclosed in any form, in whole or in part, directly or indirectly, to any
third party.

General Information

The GAI-Tronics Mine Dial/Page Telephone system combines the convenience of a telephone station
with paging capabilities in gaseous or dusty locations too hazardous for standard telephone equipment.
The system is rated as “permissible” for use in gassy coal mines by the Mine Safety and Health
Administration (MSHA) of the United States Department of the Labor (Approval Number 9B-221).

The system is used in conjunction with a touch-tone (also known as dual-tone multi-frequency [DTMF])
operated public telephone exchange or a private branch exchange (PBX). Each station in the system is
made up of two components:

• Mine Dial/Page Telephone

• Interface assembly mounted outside the hazardous area

The interface assembly is electrically connected between the station and the telephone switchboard.
Each interface assembly is connected to a separate line of the telephone exchange.

Features

The GAI-Tronics Model 491-204 Mine Dial/Page Telephone system is designed as an alternative to the
mine pager system and other communication systems (such as the “Pager” or “Loud-Speaking
Telephone”) that lack privacy and multiple conversation capabilities. The GAI-Tronics Mine Dial/Page
Telephone system includes the following features:

• Each station has a separate line. The number of independent, simultaneous conversations is limited

only by the number of stations and the capacity of the PBX.

• Stations inside the hazardous area can call any telephone outside the area, as well as any other Mine

Dial/Page Telephone station within the area.

GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA

610-777-1374  800-492-1212  Fax: [phone]

ISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS

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• Automatic circuits in the Mine Dial/Page Telephone “answer” incoming calls and permit the calling

party to page the desired person using a self-contained horn-type loudspeaker. This voice page is
preceded by a distinctive tone and is accompanied by a flashing light to assist in locating the
telephone in dark areas. The flashing light also gives visual notice of the call in high-noise areas.
The flashing light complies with Virginia and West Virginia MSHA regulations.

• A person initiating a call can page someone at a specific location without disturbing personnel at

other locations.

• The All-Call function pages all the stations simultaneously while also reaching those stations using

the system for normal conversations.

• The push button controlled, all-station page operation is activated automatically in the event of a

telephone switchboard failure.

A single pair of wires connects each Mine Dial/Page Telephone to the interface assembly. Each interface
is connected to the telephone switchboard with another corresponding pair of wires.

A person using a Mine Dial/Page Telephone station can access any station or any conventional telephone
connected to that switchboard. If the switchboard is tied into the public telephone system, an individual
can call out or receive calls from any public telephone.

Personnel in hazardous areas have direct contact to all non-hazardous areas with extension telephones
without the purchase of additional communications equipment for these non-hazardous areas.

In keeping with MSHA regulations, at least one GAI-Tronics Model 491-204 Mine Dial/Page Telephone
Station for each interface cabinet must be installed outside of a coal mine.

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Equipment Description

The GAI-Tronics Mine Dial/Page Telephone system can be configured to meet individual customer
needs. A single interface cabinet can support up to 80 Model 69001 Mine Dial/Page Telephone Station
Line Interface Cards within the Model 495-001 Mine Dial/Page Telephone Interface Cabinet. See Figure
1 for a typical system configuration and guidelines on cabling. Refer to Pub. 42004-198 for installation
and cabling of the Model 495-001 Interface Cabinet.

Figure 1. Typical System Configuration

The Model 491-204 Mine Dial/Page Telephone is contained within a corrosion-resistant, non-metallic
enclosure measuring approximately 13 × 10 × 7 inches (330 × 254 × 178 mm), not including the handset.
The handset is located in a cradle mounted to the top of the enclosure. This cradle doubles as a carrying
handle.

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