Page 1
Explosion Proof Telephone
Model EXT-401
Installation & Operation
Ph: 403.258.3100 \ email:info@guardiantelecom.com \ www.guardiantelecom.com
P002640 Rev. G 150109 1/9/2015 9:57 AM
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Guardian Telecom Inc. Installation and Operation
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Table of Contents
Table of Figures
(1) EXT-401 Telephone
(1) Installation & Operation Manual
Model EXT-401
Package Contents ...........................................................................................2
Overview .........................................................................................................3
Features ..........................................................................................................3
Warnings .........................................................................................................5
General Requirements ....................................................................................5
EXT 401 Models ..............................................................................................6
Options ............................................................................................................6
Installing the EXT-401 .....................................................................................6
Wiring For Tip & Ring ......................................................................................8
Wiring For Peripheral Signaling Device ...........................................................9
Wiring of Tip & Ring with Optional Disconnect Switch ................................... 11
Installation of Peripheral Signaling Device with Power Disconnect Switch .... 12
Fuse Replacement ........................................................................................ 13
Replacement of Telephone Handset Assembly ............................................. 14
Replacement of ISH1125 Headset ................................................................ 15
Operating Instructions ................................................................................... 16
Engineering Specifications ............................................................................ 17
Replacement Parts ........................................................................................ 18
Warranty ........................................................................................................ 20
Disclaimer ..................................................................................................... 20
Warning ......................................................................................................... 20
Service Telephone Number ........................................................................... 20
Feedback ...................................................................................................... 20
Guardian Product Return ............................................................................... 21
APPENDIX A - Hazardous Location Classification ........................................ 22
APPENDIX B - Applications ........................................................................... 23
Figure 1 - Features ..........................................................................................4
Figure 2 - Dimensions .....................................................................................4
Figure 3 - Typical Installation ...........................................................................7
Figure 4 - Lower Junction Box Wiring ..............................................................8
Figure 5 - Upper Junction Box Wiring ..............................................................9
Figure 6 - Typical Installation With Disconnect Switches ............................... 10
Figure 7 - Optional Telephone Line Disconnect Switch Wiring ....................... 11
Figure 8 - Power Disconnect Switch Wiring ................................................... 12
Figure 9 - Fuse Replacement ........................................................................ 13
Figure 10 - Handset Replacement ................................................................. 14
Figure 11 - Headset Replacement ................................................................. 15
Figure 12 - Headset Hook Switch Operation .................................................. 16
Figure 13 - I.D. and Compliance .................................................................... 18
Package Contents
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Guardian Telecom Inc. Installation and Operation
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Model EXT-401 Explosion Proof Telephone
This explosion proof telephone provides safe and reliable communication in hazardous locations, up
required. The signaling device may be actuated by an optional internal or external ring detect relay.
Enclosure
Internal Sealed Cavities
Keypad
Circuitry Coating
Magnetic Reed Hook Switch
telephone cradle.
Tone (DTMF)/Pulse Operation
Factory set to operate to tone (DTMF) exchanges unless pulse specified.
Intrinsically Safe Handset Operation
Field Replaceable Handset and Headset
Field Replaceable Fuse
Hearing-Aid Compatibility
Receiver Volume Control
Model EXT-401
Overview
to and including Class I Division 1, (see Figure 13 - I.D. and Compliance). Only standard wiring and
fittings are required to connect the telephone to the system; no barrier is necessary. Since the heavy
duty cast aluminum enclosure is basically soundproof, an external device to signal incoming calls is
Features
• Cast copper free aluminum with powder coat finish.
• Completely seal the unit.
• Standard configuration with an additional row of buttons for Last Number Redial,
Link/Flash to access PABX features and Line Release to duplicate hanging up the
handset (Link and Redial buttons may be replaced by Volume Up and Volume Down).
• One inch diameter buttons for gloves-on operation.
• Circuit boards have a UV cured epoxy coating which provides protection from
corrosive agents such as H
S, SO2, and NH
2
and environments with high humidity.
3,
• No moving parts, activates when the handset is removed from or placed in the
•
• The output from the telephone to the handset passes through an intrinsically safe
barrier ensuring a high degree of safety.
• The handset cord is attached to the telephone by a connector for ease of
replacement.
• The cord is designed for industrial applications and is available in 10’ (3m), 20’ (6m)
coiled and 22" armored lengths. An optional headset is available.
• A fitting in the bottom of the enclosure provides access to the fuse.
• The handset is compatible with inductively coupled hearing-aid devices.
• Selected models provide 13.5dB of range.
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Model EXT-401
Figure 1 - Features
Figure 2 - Dimensions
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Model EXT-401
Warnings
• In no case should this telephone apparatus or wiring be installed in a location where
acetylene may be present in the atmosphere.
• Two back cover retaining bolts on the model EXT-401 are factory sealed. Damage to the
seals voids the warranty and safety approvals, and may compromise unit safety.
• It is the responsibility of the installer to advise a supervisor if any telephone equipment or
wiring in a hazardous location may not comply with regulations and standards applicable to
that location.
• Avoid creating a spark by striking tools or metal objects together, against concrete, stone, or
any similar substance.
• Test equipment capable of producing an electric spark must not be used in an explosive
atmosphere.
• All apparatus should be completely assembled and properly sealed before reconnecting
power.
General Requirements
• An EXT-401 telephone should only be installed with proper authorization. It is necessary for
the customer and the telephone company to have a definite agreement regarding the
location of the telephone unit, auxiliary apparatus, and protector (i.e. lightning arrestor at the
demarcation block).
NOTE:
• To maintain maximum protection, broken or worn parts must be replaced immediately. Any
abnormal conditions should be immediately corrected. Periodic inspections are
recommended.
• Unless otherwise specified, the customer must provide and install explosion-proof conduit
and fittings approved by the Canadian Standards Association (CSA) or listed by
Underwriters Laboratories (UL). The customer is also responsible for having the system
inspected and approved by the appropriate electrical inspector in accordance with local
legal requirements and National Electrical Code Standards.
• EXT-401 telephone sets and associated external bells and control relays are designed to
provide security against ignition of the surrounding atmosphere. All parts of the apparatus
which might produce an electrical spark are completely enclosed. All passages to the
outside are made such that any spark or flame will be cooled to a temperature below the
ignition threshold before reaching the outside atmosphere.
• If the handset or cord is damaged, it must be replaced with part 301SC or 301SCPB
handset assembly. Handsets and cords are not covered under warranty other than to be
free of defects at time of installation.
• If the telephone is found to be defective or in need of repair, it must be returned to the
manufacturer. No field repair is possible other than replacement of the handset and fuse.
• Telephones in good condition may be moved from one location to another.
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PAR T NO.
DESCRIPTION
No Volume Control – Has LINK & REDIAL Buttons
P4011
No enhancements
P1011
Backplate & CE20 Line Powered Ringer
P4021
Ring Detect Relay
P1021
Ring Detect Relay, Backplate & CE20 Line Powered Ringer
P4022
Ring Detect Relay & Headset
P4023
Headset
P4036
Ring Detect Relay, Headset, Backplate & CE20 Line Powered Ringer
P4038
Headset, Backplate & CE20 Line Powered Ringer
Volume Control Buttons Replace LINK & REDIAL
P4012
No enhancements
P4030
Backplate & CE20 Line Powered Ringer
P4031
Ring Detect Relay
P4032
Ring Detect Relay, Backplate & CE20 Line Powered Ringer
P4033
Headset
P4034
Headset, Backplate & CE20 Line Powered Ringer
P4035
Ring Detect Relay & Headset
P4037
Ring Detect Relay, Headset, Backplate & CE20 Line Powered Ringer
installation or electrical wiring.
Installation.
peripheral equipment.
Model EXT-401
EXT 401 Models
Options
20C - Twenty foot handset cord.
22AC - 22" armored cord.
HS - Headset with thirty foot cord.
Installing the EXT-401
• Declassify the hazardous location before proceeding with any
• Follow all appropriate electrical codes and use only approved electrical
fittings for the installation.
• Choose a wall location that is free of obstructions and permits space for ½”
NPT conduit runs
• Ensure mounting can support 16.5lbs. (7.5kg), plus the weight of any
• Ensure that none of the electrical connection circuits are live.
• Use the template provided to locate and drill holes for mounting screws.
Use ¼” bolts or screws to mount the unit.
• Secure the unit to the wall:
• Attach lower conduit nipples to the telephone and ensure a minimum five
thread engagement.
• Mount an approved explosion proof junction box within 45.7 cm (18") of the
telephone’s lower sealing cavity and bring telephone wires into this box.
Fittings compatible with 1/2 inch NPT nipples, conduit, or 1/2 inch
explosion-proof flexible couplings not exceeding 45.7 mm (18 inches) may
be fitted directly.
Caution: Installation or
electrical wiring in a
hazardous location
could result in serious
injury to personnel or
damage to property.
Figure 3 - Typical
See:
See: Figure 2 -
Dimensions.
Tip: Use ¼” bolts or
screws to secure the unit
to the wall.
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Model EXT-401
Figure 3 - Typical Installation
Note: Models without volume control are not approved by the FCC and Industry Canada; they
must therefore not be connected directly to a Central Office line.
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dialing was specified. Switching in the field is not possible.
green wires and attach these wires to the ground screw in the junction box.
Model EXT-401
Wiring For Tip & Ring
• After mounting the telephone follow these steps.
NOTE: The ExT-401 is factory set for tone (DTMF) dialing unless pulse
• Run tip, ring and ground wires from the local exchange into the lower junction
box. The tip and ring wires must not be connected to the local exchange until
installation is completed. A sealing fitting must be installed within 45.7 cm
(18") on the exchange side of the lower junction box.
• Attach the tip and ring wires to the orange and blue wires from telephone
using twist on wire connectors. Attach #10 ring lugs to the end of the three
• Check the wiring and close the junction box.
TO 401
GROUND
GREEN
TIP & RING
BLUE & ORANGE
( NOT POLARITY SENSITIVE)
See: Figure 4 - Lower
Junction Box Wiring
Figure 4 - Lower Junction Box Wiring
FROM EXCHANGE
TIP
RING
GROUND
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Guardian Telecom Inc. Installation and Operation
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of the telephone.
power lead. Attach wires by the use of twist-on wire connectors.
Model EXT-401
Wiring For Peripheral Signaling Device
• Mount the upper junction box within 45.7 cm (18”) from the top of the
telephone. Install conduit and signaling device wires to the upper junction box
See: Figure 3 - Typical
Installation
• In the upper junction box, connect the incoming power hot lead to one of the
white wires from the EXT-401 internal ring detect relay. Connect the other
wire from the EXT-401 relay to one of the wires from the auxiliary signal
device. Connect the other wire from the auxiliary signal device to the neutral
• Secure the ground wire to the junction box ground screw.
• Check wiring and close the junction box.
See: Figure 5 - Upper
Junction Box Wiring
Figure 5 - Upper Junction Box Wiring
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maximum
Model EXT-401
Figure 6 - Typical Installation With Disconnect Switches
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complete and ready for use.
Model EXT-401
Wiring of Tip & Ring with Optional Disconnect Switch
NOTE: The ExT-401 is factory set for tone (DTMF) dialing unless pulse
dialing was specified. Switching in the field is not possible.
• Mount an approved explosion proof disconnect switch within 45.7 cm (18") of
the lower junction box and install a flexible coupling or conduit with a sealing
fitting between the two.
• Ensure the disconnect switch is in the OFF position until the installation is
See: Figure 7 - Optional
Telephone Line
Disconnect Switch
Wiring
• Pull the tip, ring, and ground wires (18ga) from the disconnect switch to the
lower junction box of telephone. Fill the sealing fitting with sealing compound
as described in the instructions supplied by the manufacturer.
• Attach the tip and ring wires to the orange and blue wires from the telephone
using twist on wire connectors. Attach #10 ring lugs to the end of the three
green wires and attach these wires to the junction box ground screw.
• Inside the disconnect switch box attach the tip, ring and ground wires
according to wiring diagram for the disconnect switch. Do not connect the tip
and ring wires at the local exchange until installation is complete.
• Check wiring of junction box and power disconnect switch box before closing.
See: Figure 4 - Lower
Junction Box Wiring
See: Figure 7 - Optional
Telephone Line
Disconnect Switch
Wiring
Figure 7 - Optional Telephone Line Disconn ect Switch Wiring
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Hot Lead
Hot Lead
Neutral Lead
Neutral Lead
Ground
Ground
On
Off
Ground Screw
To Upper
Junction Box
From Power Source
Model EXT-401
Installation of Peripheral Signaling Device with Power Disconnect Switch
• Mount the auxiliary signaling device in the desired location above the
telephone. Run conduit and signaling device wires to the upper junction box.
• Mount an approved power disconnect switch within 45.7 cm (18") of the
upper junction box and install a flexible coupling or conduit with a sealing
fitting between the two. Pull three wires (18ga) from disconnect switch to
upper junction box. Fill the fitting with sealing compound as shown in the
manufacturer's instructions.
• In the upper junction box, connect the incoming power hot lead to one of the
wires from the EXT-401 internal ring detect relay. Connect the other wire
from the EXT-401 relay to one of the wires from the auxiliary signaling
device. Connect the other wire from the auxiliary signaling device to the
neutral power lead. Attach wires using a twist-on wire connector.
• Secure the ground wire from the power disconnect switch to the junction box
ground screw.
• Ensure the disconnect switch is in the OFF position until installation is
complete and the unit is ready for use. In the power disconnect switch box,
attach the hot wire, neutral wire, and ground wires according to wiring
diagram for the power disconnect switch box.
• Check the power disconnect switch and upper junction box before closing.
See: Figure 8 - Power
Disconnect Switch
Wiring
See: Figure 5 - Upper
Junction Box Wiring
Figure 8 - Power Disconnect Switch Wiring
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Model EXT-401
Fuse Replacement
• Disconnect the telephone from tip and ring power supplied by the PABX or
central office before attempting to replace the fuse.
• Remove the 1/2” NPT close up plug (item A) with a 1/4” Allen key.
• Remove fuse holder cap (item B) with a flat blade screwdriver. Rotate fuse
holder cap 1/4 turn counterclockwise (to the left) to remove.
• Remove fuse (item C) from the cap and insert replacement fuse.
See: Figure 7 - Optional
Telephone Line
Disconnect Switch
Wiring
See: Figure 9 - Fuse
Replacement
WARNING!
• Replace only with a 0.25 amp 2AG fast blow fuse. Failure to do so will void
safety approval and warranties and may create an explosion hazard.
• With fuse mounted in the cap, re-install in the fuse holder with a flat blade
screwdriver and rotate 1/4 turn clockwise (to the right) to lock in position.
• Screw the 1/2” NPT close-up plug into housing with a minimum of five full
threads of engagement.
ATTENTION!
• CSA & UL standards require five full threads of engagement for the close-up
plug.
NOTES
• A field replaceable fuse is available on EXT-401 models manufactured after
Jan. 1, 1997.
• If, on reconnecting power, the fuse fails, check the telephone system wiring.
The fuse protects the tip and ring line from the telephone system. It is usually
powered at 48 volts DC and should not be connected to 120 volts AC.
See: Product
Specifications
Figure 9 - Fuse Replacement
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Guardian Telecom Inc. Installation and Operation
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PRIOR
use a wrench.
Model EXT-401
Replacement of Telephone Handset Assembly
Note: The standard handset assembly for the EXT-401 telephone has a 3.0 m
(10 ft) coiled cord. A 6.0m (20 ft) long coiled cord and a 22" armored cord are
available as options. These assemblies are designed specifically for use with the
EXT-401 telephone. If damaged the assembly may be replaced in the field. Only
a 301SC, 301SCPB (push to talk) or 22AC-401 armored cord handset assembly
may be used with the EXT-401 telephone. Alternatively an ISH1125 headset
assembly may be used in place of a handset.
• Completely unscrew the upper knurled collar.
• Pull the old plug straight down.
• Inspect the inside of the socket and the threads for dirt or damage; clean as
necessary.
• For safe installation, the new handset MUST be placed firmly in the cradle
to engaging the plug in socket.
• Bring the new plug up to the socket and rotate the plug until the slot in the
shell lines up with the key in the socket. Insert plug into socket.
• Screw the upper knurled collar onto the socket. Hand tighten only, Do Not
• Call back and forth to another set to check functionality.
• Hang up firmly between each call.
• NOTE: If the handset is being replaced because of an apparent telephone
malfunction, and the replacement fails to restore normal operations, contact
the manufacturer to arrange return of the unit for repair.
See: Figure 10 Handset Replacement
Figure 10 - Handset Replacement
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Guardian Telecom Inc. Installation and Operation
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Model EXT-401
Replacement of ISH1125 Headset
• Note: The headset cord is a 9.1 m (30 ft) long coiled cable designed
specifically for use with the EXT-401 telephone. If damaged, the assembly
may be replaced in the field. Only an ISH1125 headset assembly or a 301SC
or 301SCPB (push to talk) handset assembly may be connected to the EXT401 explosion proof telephone.
• Completely unscrew the upper knurled collar.
• Pull the old plug straight down.
• Inspect the inside of the socket and the threads for dirt or damage; clean as
necessary.
• For safe installation, the new headset MUST be placed on the headset arm
PRIOR to engaging the plug in socket.
• Bring the new plug up to the socket and rotate the plug until the slot in the
shell lines up with the key in the socket. Insert plug into socket.
• Screw the upper knurled collar onto the socket. Hand tighten only, Do not
use a wrench.
• Call back and forth to another set to check functionality.
• Hang the headset onto the hook switch arm between each call.
• NOTE: If the headset is being replaced because of an apparent telephone
malfunction, and the replacement fails to restore normal operations, contact
the manufacturer to arrange return of the unit for repair.
See: Figure 11 Headset Replacement
Figure 11 - Headset Replacement
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Guardian Telecom Inc. Installation and Operation
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See:
Model EXT-401
Operating Instructions
EXT-401 TELEPHONE WITH HANDSET OR HEADSET
Handset
• Remove handset from cradle.
• Listen for a dial tone and then dial the appropriate digits for the feature
desired.
• Upon completing a call hang up by returning the handset to the cradle.
• Calls are answered by lifting the handset from the cradle.
• To make another call without returning the handset to the cradle, press the
RLS (release) button.
Headset
• Remove the headset and place it over the head; raise the hook switch arm
to the off hook (vertical) position.
• Listen for a dial tone and then dial the appropriate digits for the feature
desired.
• Ensure that the belt hook TALK/MUTE switch is in the TALK position. This
switch does not affect voice reception or control on-hook/off-hook operation
of the telephone.
• Upon completing a call, return hook switch arm to the on-hook (horizontal
position).
• Calls are answered by lifting the hook switch arm.
• To make another call without returning the headset to the hook switch arm
press the RLS (release) button.
Figure 1 - Features
See: Figure 12 Headset Hook Switch
Operation
See: Figure 11 Headset Replacement
Figure 12 - Headset Hook Switch Operation
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Electrical Performance
DETECT RELAY INSTALLED
Electrical Requirements
Environmental
Mechanical
TEMPERATURE POLYURETHANE JACKET
T
Model EXT-401
Product Specifications
AUDIBLE RANGE FREQUENCY RESPONSE 300 – 3400 HZ
DIALING METHOD DTMF OR 40/60 PULSE, 10 PPS
TRANSMIT OBJECTIVE LOUDNESS RATING (TOLR) -38 +/- 4 dB
RECEIVE OBJECTIVE LOUDNESS RATING (ROLR) TYPICAL 52 +/- 4 dB
SIDE TONE OBJECTIVE LOUDNESS RATING (SOLR) TYPICAL 20 +/- 3 DB
RINGER OUTPUT N/A
FCC RINGER EQUIVALENCE WITH OPTIONAL RING
0.9 A, 1.9B
RING DETECT RELAY RATINGS (OPTIONAL) 10 AMPS AT 250VAC
FLASH 600 MSEC TIMED DISCONNECT
REDIAL 13 DIGITS MAXIMUM
MAXIMUM LOOP 15 KFT OF 22 AWG COPPER
LINE VOLTAGE 24 – 56 VDC
LOOP CURRENT 20 - 120 MA
RINGER DETECT RELAY SENSITIVITY (OPTIONAL) 40 – 100 V, 16 – 25 HZ
CONNECTION METHOD FACTORY SEALED WIRING THROUGH ½” CONDUIT ENTRY
FUSE 2AG 0.25 AMP 250 VOLT
WEATHERPROOF & WATERTIGHT ENCLOSURE NEMA 4
TEMPERATURE -40
O
TO +60
O
C (-40
O
TO 140
O
F)
HUMIDITY 0 TO 95% RH NON CONDENSING
DUSTPROOF ¾” FLAT FLANGE DUSTPROOF JOINTS
HOOK SWITCH (CRADLE SWITCH) LIFE >1 000 000 OPERATIONS
BODY CONSTRUCTION COPPER FREE CAST ALUMINUM WITH POWDER COAT
DIMENSIONS 325 X 173 X 122 MM (12.8 X 6.8 X 4.8 INCHES)
NET WEIGHT 7.95 KG (17.5 LBS.)
HANDSET MATERIAL HIGH IMPACT ABS
HANDSET CORD 3.0 M (10 FT) FIELD REPLACEABLE WITH LOW
HANDSET CORD (OPTIONAL) 6.0 M (20 FT) FIELD REPLACEABLE WITH LOW
MICROPHONE DYNAMIC
FINISH
EMPERATURE POLYURETHANE JACKET
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Guardian Telecom Inc. Installation and Operation
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Compliances
CLASS II, DIVISION 1, GROUPS E, F & G
Part No.
Description
P007130
Push-to-Talk Handset Assembly C/W 10 foot Curly Cord
Model EXT-401
RECEIVER HEARING AID COMPATIBLE
DIAL PAD OVERSIZED ALUMINUM BUTTONS ON 1.125” GRID
STANDARD MOUNTING VERTICAL WALL
CONNECTION FITTINGS ½” NPT CONDUIT ENTRY
INDUSTRY CANADA 1012 4339 A
FCC HQHCAN-65560-TE-E
CSA LR65547-18
UL 13X8, & E117495
WEATHERPROOF & WATERTIGHT ENCLOSURE NEMA 4
HAZARDOUS LOCATION APPROVALS CLASS I, DIVISION 1. GROUPS B, C & D
ENVIRONMENTAL SURVIVABILITY MIL-STD-810E
ONLY MODELS WITH VOLUME CONTROL – SEE EXT 401 MODELS
Figure 13 - I.D. and Compliance
P007111 Standard Handset Ass embly C/W 10 foot Curly Cord
P007121 Standard Handset Assembly C/W 20 foot Curly Cord
P005574 Standard Handset Assembly C/W 22" Armored Cord
P007131 Push-to-Talk Handset Assembly C/W 20 foot Curly Cord
P007221 Headset Assembly C/W 30 foot Curly Cord
P004022 Fuse – 2AG 0.25 Amp 250 Volt Fast Blow
Replacement Parts
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Guardian Telecom Inc. Installation and Operation
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Model EXT-401
Government Certification
Attached to the tel ephone are labels for Industry Canada and t he United States Federal Communications Commission. These identify
equipment certifications indicating the 60 and 70 series telephones meet c ertain telecommuni cations network protective, operational
and safety requirements. These agencies do not guarantee t he equipment will operate to the user's satisfaction.
Before install ing this telephone equi pment, users shoul d ensure it is perm issible to connect t he equipment to facilities of the local
telecommunicat ions company.
Equipment must be i nstalled using acceptable connection methods. In some cases, the telephone users inside wiring, associated with
a single line ser vice, may be extended by a certified connector assembly (tel ephone extension cord). The customer should be aware
that in some situations compliance with the above conditions may not prevent degradation of service.
Repairs to certified equipment should be made by a supplier designated authorized maintenance fac ility.
For their own protection users should ensure the electri cal ground connections of the power utilit y, telephone lines and i nternal
metallic water pipe systems, if present, are connected. This precaution may be particularly i m portant in rural ar eas.
CAUTION: Users should not attempt to make ground connections, but should contact the appropriate electrical inspection authority
or electrici an.
Load Number (LN)
The Load Number (LN) assigned to each terminal device denotes the percentage of the total load to be connect ed to a telephone loop
used by the device. Termination on a loop may c onsist of any combination of devices s ubject only to the requirem ent that the total of
the Load Numbers of all the devices does not exceed 100.
Notification to Telephone Co m pany
Upon request, the customer must notify the telephone company of the particul ar line to which the connection will be made and provide
the Industry Canada or FCC registrat ion number. The local telephone company may r equest disconnec tion of the telephone where
alterations or m alfunctions affect the telephone’s performance.
United States Federal Communications Commis sion
This equipment gen erates, uses and can r adiate radio frequency energy, and if not installed and used in accordance with the
instruction manual, may cause interference to radio communications. It has been tested and found to comply with the li mits for Class
A computing devic e pursuant to Subpart J of Part 15 of FCC rules, which are designed to pr ovide reasonable protection against such
interference when operated in a commercial environment. O peration of this equipment in a residential area is likely to cause
interference i n w hich case the user, at his own expense, will be required to take whatever measures may be required to correct the
interference.
Interference
There is no guarantee that interferenc e w ill not occur in a par ticular installation. If interf erence to radio or television reception from this
equipment is suspected, proceed as f ollows:
1. Unplug the set, check for the interfer ence.
2. Re-orient the receiving antenna.
3. Relocate the set with respect to the receiver.
4. Move the set away fr om the receiver.
If necessary, consult the supplier or an experienced radio/television tec hnician for additional suggestions.
FCC Rules and Ringer Equivalence Number
This equipment c om plies with Part 68 of the FCC Rules. On the s ide of this equipment is a label that contains, among other
information, t he F CC registration number and ringer equivalence number (REN) for this equipment. If requested, this information
must be provided to the telephone company.
The REN is used to determine the quantity of devices which may be connected to the telephone line. Excessive RENs on the
telephone line may result in the devices not ringing in response to an incoming call. In most, but not all areas, the sum of the R EN s
should not exceed five. To be certain of t he num ber of devices that m ay be connected to the line, as determined by the total RENs,
contact the tel ephone company to determ ine the maximum REN f or the calling area.
Service changes and L imitations
The telephone company may make changes in its facilities, equipment, operations, or procedures that could affect the operation of the
equipment. If this happens, the telepho ne company will provide advance notice i n order for you to make the necessary modifications
in order to maintai n uninterrupted service.
This equipment cannot be used on public coin telephone service as provided by your telephone company. Connection to party l ine
service is subject to state tariffs (contact the state publ ic utility commission, public servi ce commission or corporate commissi on for
information.)
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Guardian Telecom Inc. Installation and Operation
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Guardian Telecom warrants your product to be free of defects in material and workmanship for a period
This warranty is null and void if any non-authorized modifications have been made to this product, or if
responsible for costs incurred for on-site service calls, freight, or brokerage.
A return authorization must be obtained prior to warranty claims or repairs.
The products covered by this manual are designed for use in Industrial Environments and/or Hazardous
consequential damages.
Guardian’s Model EXT-401 Explosion Proof telephone must NOT be opened by the user, doing so
Guardian Telecom provides a customer service telephone number which is toll-free within North
with your return address and the name of the person to contact.
www.guardiantelecom.com
Guardian Telecom continually strives to make reliable, durable, and easy to use products. If you, as an
or documents, including this manual, we would appreciate hearing from you.
Model EXT-401
Warranty
of one year. Guardian Telecom will repair or replace any defective unit that is under warranty free of
charge.
it has been subjected to misuse, neglect, or accident. This warranty covers bench repairs only; such
repairs must be made at Guardian Telecom or an authorized service depot. Guardian Telecom is not
Disclaimer
Locations. Due to the range of possible applications for these instruments the manufacturer will not be
responsible for damages or losses of any kind suffered as a result of the use of this product, including
Warning
voids the warranty and safety approvals. The EXT-401 handset and fuse are externally accessible
parts which may be safely serviced by the user following procedures described in the manual.
Service Telephone Number
1-800-363-8010
America. If you need assistance when installing or operating this product, please call the toll-free
telephone number between regular business hours (8:00AM-5:00PM), Mountain Standard Time. If you
are calling outside of regular business hours, please leave a detailed message, and a membe r of
Guardian Telecom’s Service Department will return your call as soon as possible. If your product
requires service, Guardian personnel will supply you with an RMA (return materials authorization)
number over the telephone or through our web site product return page. This number must be included
Guardian Telecom Inc.
Toll-free 1-800-363-8010
Ph. (403) 258-3100
Fax. (403) 253-4967
Feedback
installer or user of our equipment, have any suggestions for improvements to this or any of our products
Page 21
Guardian Telecom Inc. Installation and Operation
Page 21
Guardian products have been quality tested and are in full working order when shipped from
unit. In the unlikely event of a malfunction, Guardian follows the three step procedure below.
product.
Model EXT-401
Guardian Product Return
the factory, given the rugged nature of these products shipping is not expected to damage a
Step I - On-Site Correction
• The most common source of difficulties with a new product is improper installation in one of
two ways: incorrect wiring connect ions or conn ectio n to an incorr ect power source.
• Product wiring needs to be properly connected to the on-s ite wirin g. Correc t wiri ng
instructions are shown in the user manual included with the product.
• Connecting a telephone to a standard power source, rather than tip & ring, will blow the
telephone’s internal, user-replaceable fuse. In the event of fuse burn-out, disconnect the
telephone from the power source, replace the fuse, and reconnect following the wiring
diagrams provided with the product.
Step II - Return Materials Authorizat ion (RMA)
• When a product has been installed following user manual instructions, and the unit fails to
operate, the user must contact Guardian Telecom to obtain authorization to return the
product. This can be done by completing a RMA form online at
www.guardiantelecom.com, or by calling the service telephone number given in this
manual.
• After providing information on the product, the owner and the nature of the problem,
Guardian will issue a RMA number, to be shown on documentation returned with the
• In addition to the RMA number, shipping documents should include name, address and
telephone number of the owner along with contact information for the person responsible
for the repair and/or the user who identified the malfunction.
• (Where a product is being returned for repair from outside of Canada, customs
documentation must show the product’s serial number, date of export [date of purchase],
and a notation that the equipment is: “Canadian goods returning.”)
Step III - Factory Authorized Service
• Once received, each product is carefully inspected and tested. If the product is under
warranty, repairs are completed and the product returned to the owner, generally within
five working days of receipt by the factory.
• A product that has been subjected to misuse, neglect or accident or is beyond the warranty
period will be evaluated. The service department will provide the owner’s representative
with a repair cost estimate. Once approved, repairs are completed and the product
returned, generally within five working days.
Page 22
Guardian Telecom Inc. Installation and Operation
Page 22
Model EXT-401
APPENDIX A - Hazardous Location Classification
CLASS I, DIVISION 1 & 2, GROUP B
acrolein formaldehyde(gas) propyl nitrate
butadiene hydrogen ethylene oxide
manufactured gases containing more than 30% hydrogen(by volume) proplene oxide
CLASS I, DIVISION 1 & 2, GROUP C
acetaldehyde epichlorohydrin methyl formal
allyl alcohol ethylene methyl mercaptan
butyl mercaptan ethylenimine monomethyl hydrazine
n-butyraldehyde ethyl mercaptan morpholine
carbon monoxide n-ethyl morpholine nitroethane
crotonaldehyde hydrogen cyanide nitromethane
dicyclopentadiene hydrogen selenide 2-nitropropane
diethyl ether hydrogen sulfide propionaldehyde
diethylamine isobutyraldehyde n-propyl ether
di-isopropylamine Isopropyl glycidyl ether tetrahydrofuran
dimethylamine methylacetylene triethylamine
1,4-dioxane methylacetylene-propadiene unsymet rical dimethyl hydrazine
di-n-propylamine methyl ether valeraldehyde
CLASS I, DIVISION 1 & 2, GROUP D
acetic acid ethyl benzene methyl isocyanate
acetone ethyl chloride methyl methacrylate
acetonitrile ethylenediamine 2-methyl-1-propanol
acrylonitrile ethylene dichloride 2-methyl-2-propanol
allyl chloride ethyl glycol monomethyl ether naptha
ammonia (3) ethyl formate nonane
n-amyl acetate gasoline nonene
sec-amyl acetate heptane octane
benzene heptene octene
butane hexane pentane
1-butanol (butyl alcohol) 2-hexanone 1-pentanol
2-butanol (secondary butyl alcohol) hexenes 2-pentanone
n-butyl acetate isoamyl acetate 1-pentene
sec-butyl acetate isoamyl alcohol petroleum naptha
butylamine isobutyl acrylate propane
butylene isoprene 1-propanol
chlorobenzene isopropyl acetate 2-propanol
chloroprene isopropylamine n-propyl acetat e
cyclohexane isopropyl ether propylene
cyclohexene liquefied petroleum gas propylene dichloride
cyclopropane mesityl oxide pr op ylene ox ide
1,1-dichloroethane methane pyridine
1,2-dichloroethylene methanol styrene
1,3-dichloropropene methyl acetate toluene
di-isobutylene methyl acrylate tripropylamine
ethane methylamine turpentine
ethanol methylcyclohexane vinyl acetate
ethyl acetate methyl ethyl ketone vinyl chloride
ethyl acrylate methyl formate vinylidene chloride
ethylamine methyl isobutyl ketone xylenes
Page 23
Guardian Telecom Inc. Installation and Operation
Page 23
The EXT-401 Explosion Proof Telephone has been approved by Canadian Standards Association
(CSA) and listed by Underwriters' Laboratories (UL) for use in explosive atmospheres.
Locations that may require explosion-proof equipment include:
gas plants
tankers and tanker depots
Model EXT-401
APPENDIX A (cont.)
CLASS II, DIVISION 1 & 2, GROUP E
Atmospheres containing combustible metal dusts regardless of resistivity, or other combustible dusts of
similarly hazardous characteristics having resistivity of less than 105 ohm-centimeter
CLASS II, DIVISION 1 & 2, GROUP F
Atmospheres containing carbon black, charcoal, coal or coke dusts which have more than eight percent
total volatile material (carbon black per ASTM D1620; charcoal, coal and coke dusts per ASTM D271)
or atmospheres containing these dusts sensitized by other materials so that they present an explosion
hazard, and having resistivity greater than 100 ohm-centimeter but equal to or less than 108 ohm
centimeter.
CLASS II, DIVISION 1 & 2, GROUP G
Atmospheres containing combustible dusts having resistivity of 100000 ohm-centimeter or greater.
NOTE: This appendix is a summary of information contained in the National Electrical Code. Please
refer to local applicable Electrical Codes for details and latest update.
• chemical plants
• petrochemical plants
• offshore drilling r ig s
• land-based drilling rigs
•
• oil & gas metering facilities
• refineries
• fueling stations
• breweries and distilleries
APPENDIX B - Applications
• defense installations
• munitions storage depots
• missile silos
• liquefied natural gas terminals
•
• paint and varnish manufacturing plants
• grain processing and similar industries
• bulk loading stations
• fertilizer plants
Page 24
Guardian Telecom Inc.
Toll-free 1-800-363-8010
Phone (403) 258-3100
Fax. (403) 253-4967
www.guardiantelecom.com
E-mail: sales@guardiantelecom.com
(Click to open message box)
CONNECTED. PROTECTED.
© Guardian Telecom Inc. 2015
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