GAI-Tronics 700 User Manual

Pub. 42004-139D

GAI-TRONICS® CORPORATION

A HUBBELL COMPANY

700 Seri es

Page/Party

Confidentiality Notice

This manua l is provide d sole ly as an operatio nal, installation, and ma inte nance guide and conta ins
sensitive business and t e chnical informatio n tha t is confidentia l and pr opri et ary to GAI- Tronics. GAI­Tronics retains all intellectual property and other rights in or to the information contained herein, and
such information may on ly be u sed in conn e ction with the operatio n of you r GAI-Tr onics p rodu c t or
system. This manu al may not be dis clos e d in any form, in whole or in pa rt, direct ly or i ndir ectly, to a ny
third pa r ty.

General Information

The GAI-Tronics Page/Party® System is a modular industrial communication system incorporating from
two t o poss ibly hundreds of sta tions. Avai labl e i n sev e ral f orms, each stat ion includes a han dset, two
amplifiers (one for the handset and the other to drive one or more paging speakers), associated controls,
and a paging speaker ( usually mounte d sepa rately). All s tatio ns ar e wired in par allel and additiona l
stations may b e added at a ny time.

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Systems

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A GAI-Tronics Page/Party
station locations carefully, taking convenience, accessibility, and personal safety into account. The
quantity and location of paging speakers must be carefully considered, particularly in areas of high
ambient noise or reverberation. The speaker amplifier built into each station drives one horn-loaded page
speaker. If additional paging speakers are needed, separate speaker amplifiers can be added to the
system. In quiet areas, such as offices, several paging speakers can be connected to a single station.
Please refer to Pub. 42004-135, Speaker Installation, or consult with a GAI-Tronics sales representative
for additional system planning information.

All units a re wire d in parallel. Good planning will minimize th e cable required f or eac h installat ion.
GAI-Tronics Corporation can supply multi-conductor cable designed especially for this application. The
number, size and color-coding of conductors are listed in the accompanying system connection diagrams.
Standard cable has 600-volt insulation and is UL-rated for power cable tray use. Additionally, for ease of
installation GAI-Tronics’ cable is color-coded to match the termination points in our enclosures. The
maximum standard cable length is 5250 feet (1600m) from the Line Balance Assembly systems. For non­standard ca ble, please contact a GAI-Tr onics representative.

The cable described above includes conductors to provide ac operating power to each station. All stations
operate from a common source, enhancing reliability, particularly if no other ac load is placed on the
circuit breaker or branch line feeding the system. This configuration also allows easy transfer to an
emergency power source in the event of power failure. However, if preferred, each station may be
individually powered from a nearby nominal 115 volt, 50 or 60 Hz single phase outlet.

System layout should be planned in advance of installation. Select handset

GAI-Tronics Corporation P.O. Box 1060, Readi ng, PA 19607-1060 USA

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

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

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Installation Procedure

Step 1 — Electrical Noise Consideration s

When planning your system, consider the following suggestions to avoid electrical noise caused by slip
rings and silicon control rectifier (SCR) power supplies.

Slip Rings - Use a ra dio fre quency (RF) alterna tiv e and avoid using slip rings as audio co nductors . Slip

rings ar e a sour ce of el ect rical noise an d a re not reliable.

SCR Power Supplies - If the Page/Party

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system will be installed in areas where SCR power supplies
ar e u sed to p ower motors or oth er heavy equipme nt, consider using o ne or all of the followi ng fou r
recommendat ions to reduce el ectrical noise.

1. Separation—Locate the Page/Party

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system cables as far as possible from the SCR power supply
input or output cables. Electrical coupling between cables is reduced by the square of the distance
between the cab les.

2. Shielding—Use shielded (armored) system cables if the cable must be run in the same bundle or cable

tray with the SCR power supply cables. Shielded cables reduce capacitive coupling between SCR

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power supply cables and Page/Party

3. Isolation—Two methods of power source isolation can be used to avoid electrical noise:

A. Use a low capacitance (primary to secondary) isolation transformer between the Page/Party

and the ac supply to the SCRs. This electrically isolates the Page/Party

audio cables.

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system’s ac power from the

system

noise generated by the SCR on the ac power feed. Also use an isolation transformer to isolate the
Page/Party

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ac power from an ungrounded ac power source. Note: The neutral side of the

transformer ou tput must be ground e d in al l instances.

The size of the isolation transformer should be based on the number of amplifiers used in the system.
If ten or less amplifiers are used in the system, a 500 VA transformer is sufficient. If 11 to 20
amplifiers are used in the system, select a 1000 VA transformer. For systems with more than 20
amplifiers, the transformer should be sized to accommodate a load of 50 VA per amplifier.

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B. A battery powered 24 V Page/Party

system can be used as an alternative to the standard 120 V ac
system. In this instance, the battery/battery charger provides isolation from the SCR noise on ac
power systems. Cable shielding and separation as mentioned above still apply.

OTE: Avoi d bat tery cha rgers tha t utilize SCRs in their design.

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Step 2 — Mounting of Station and Spea ker Amplifier Enclosure

Each Page/Party® system station includes a plug-in amplifier, that mates with a fabricated steel, cast
aluminum, or molded reinforced non-metal lic en cl osu re. Each enclosure provides a t erminal strip for
connecting inter-station cable. Enclosures are packed separately from the plug-in amplifiers at the
factory, allo w ing the amplifiers to remain p rotected w hile t he enc losures are installed and wired —
particularly important during system installation in areas under construction.

The 16-gauge steel enclosures do not provide any openings for conduits or cables because the location of
these wil l vary w ith each instal latio n. Dr ill or punch th e n ecess ary openings b efore mount ing the
enclosure. Loc at e the ope nings either along the top o r bo ttom of th e enclosure a nd near the rea r s u rface.
Avoid the top center because of possible interference with the plug-in amplifier receptacle. A drill
template is supplied with each enclosure.

Cast aluminum enclosures are drilled and tapped on the top and bottom for specially-designed hub plates.
Unless special arrangements are made, the enclosures include plates for single 1¼-inch conduit. Plates
for single ½-inch or 1½-inch, or dual inch are available. The molded enclosures are supplied without any
conduit op enings. Sealed threaded hubs, su ch as M yers “S cru-tite”, ar e reco mm end ed. A dr il l template is
supplied with each enclosure.

CAUTION

Use caution when drilling holes to avoid damaging internal electrical components and wiring.

Suggested mounting height for all station enclosures is 54 inches (137 cm). Subsets used with remote
subset amplifiers are supplied with 8-foot (244 cm) cables. Enclosures for remote subset amplifiers must
be mounte d within r each of the 8-foot c abl e. Desktop or desk-ed ge stations enclosures are often mounted
in the knee-well of the desk.

Step 3 — Mounting of Line Balance Ass embly

Eac h G AI-T ronics Page/ Party® system requires one line balance assembly. Its function is to properly
load the page and party line circuits. When using GAI-Tronics standard cable, select a location that is:

• near the elect rical center of t he system

• adjacent to an indoor station in a relatively quiet area

• no more than 5250 feet (1600m) from the most distant station

For larger systems or when using other types of cable, contact a GAI-Tronics representative for further
information. The line balance assembly has one electrical adjustment that must be made while using a
station (see below). The following is the preferred method for mounting the line balance assembly:

1. Suspend the assembly from the lower side of the indoor wall station using a 1-inch conduit nipple

(not supplied).

2. Connect one twisted pair wire for the page circuit and another for each of the party lines between the

terminal blocks of the line balance assembly and the associated indoor wall station.

3. Make the wiring connections between the 305 Series Line Balance Assembly and the Model 702 and

703 Indoor Wall Station enclosures in accordance with the wiring diagrams at the end of this
publication.

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Step 4 — Installation of Inter-station Co nduit and Cable

Inter-station cables are generally installed in cable trays or conduit. To assist in determining the conduit
sizes required, the outside diameters of the GAI-Tronics Corporation cables discussed in this publication
are listed below. Size and installation of conduit and cable must meet the requirements of applicable
electrica l c o d es.

Cable Conductors O.D.

60038-101 8 0.60 in. (15.1mm)
60029-101 16 0.68 in. (17.2mm)

A ground conductor, with green/yellow insulation, should be included with cable in any area where no
conduit or non-metallic conduit is used. Non-metallic enclosures used with metallic conduit and cable
without a ground conductor require a bond between the conduit(s) and the ground terminal (point 3)
within the enclosure.

When using GAI-Tronics cable, attach wire lugs to each conductor and connect to the terminal in
accordance with either the color code shown on the applicable accompanying diagram or with special
drawings provided for this purpose.

Exception: Some cables have a n or a nge “spare” cond ucto r. Unless otherwis e i ns tructed, this
should be tape d and not connected to the termina l strip(s) in the enclosures.

GAI-Tronics cable is considered to be a Class 1 cable (maximum voltage is less than 600 V). In a cable
tray, C lass 1 cable ma y only be groupe d with other Class 1 cables. Long runs of GAI-Tronics cabl e in
proximity to 600-volt cable may cause an undesirable amount of hum being induced onto the Page/Party
system’s signa ling lines . To r edu ce un desired hum, it is r ecommended t hat runs of c able ov er ½ mil e be
separated from 600-volt cable by a minimum of 12 inches.

Step 5 — Installation of Amplifiers and Subsets

One of the many feat ur es of GAI-Tron ics Pa g e/Party® system equipment is automatic speaker muting.
When the push-to-page switch is pressed at a particular station, the paging speaker connected to that
station is silenced, preventing acoustic feedback to the handset microphone. However, while the handset
is in use for the party line conversations, the paging speaker is still “live” t o paging calls from oth er
stations.

For cases where the muting feature is not necessary or may be a disadvantage, it can be defeated as
outlined below:

1. Locate lugged violet wire attached to terminal point 7 (Mute) on the terminal block within the

enclosure for station to be modif i ed.

2. Transfer lugged violet wire to terminal point 8 (Page L1).

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After making any necessary muting changes, unpack and install the amplifier for each station. Also,
unpack remote subsets (for desktop, desk-edge or panel-mount stations) and plug each into the bottom
sides of the amplifier enclosure.

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Step 6 — Checkout and Adjustment

Test all field wiring connections (page line, party line(s), mute, ac power and speaker) between stations,
and complete the line balance assembly installation before checkout begins. Ensure that all handsets are
on-hook.

1. App ly ac power, and check the st atio n next to the line balance a ssemb ly.

2. Press the “push-to-page” switch (in the handset handle on some stations) and speak directly into the

microphone of the handset. The broadcast should be heard at all paging speakers in the system except
those associated with the station under test. If working properly, very little or none of your own voice
(sidetone) is heard from the handset earpiece. If the line balance assembly is not connected properly,
there will be a high level of sidetone, perhaps enough to cause feedback. Adjust the line balance
assembly to optimize sidetone rejection on the page line. If the system is complete when the first
station is checked, adjust the li n e b alan ce assembl y as noted bel ow. Do not ad just station
(amplifier) controls until the line b a lance assembly i s adj us t ed.

3. Release the push-to-page switch and check the party line(s) sidetone level by speaking into the

microphone of the handset. If working properly, very little or none of your own voice is heard from
the handset earpiece. This sidetone rejection will only occur if the line balance assembly is properly
connect e d beca use it c onta ins a fixed resistor load for eac h party line. In addition, no party line
adjustme nts are pr ovided. Check party line operation by conver sing bet w e e n two or mor e stations.

Adjustmen t of the Line Balance Assembl y

To s et the contro l for proper pa ge circuit loadin g:

1. Remove the line balance assembly cover to expose the line balance control.

2. Lift the handset from the adjacent handset hook and press the push-to-page button.

3. From the normal speaking distance (approximately ½-inch), blow steadily into the handset

microphone and adjust the control to minimize receiver sidetone. This adjustment needs to be made
only at the initial installation of the system. However, if in the future more than 10 speaker amplifiers
are added or deleted, repeat adjustment of page circuit loading.

4. After final adjustment, replace and secure the cover with the four mounting screws to discourage

tampering by unauthorized personnel and prevent entry of contaminants.

Each amplifier has a paging speaker volume control. It is accessible from the front panel with a
screwdriver, but is concealed behind the metal nameplate. To reach it, simply loosen (do not remove) the
two nameplate screws and pivot the nameplate around the left screw. This control is adjusted at the
factory so that a moderate page level produces 4 watts of output power.

Each handset/s peak er station amplifier has t w o addit ional internal c ontr o ls: receiv er volu me cont rol an d
receiver sidetone control, both accessible using a screwdriver through the holes in the chassis. A third
hol e allows similar access f rom the rear of the pa ging sp eaker volume control. Both controls are
factory-adjuste d f or optimum results in most industrial applicati ons. Do not readjus t these controls to
solve system problems until other possible faults are checked, such as a missing, defective, or improperly
conne ct ed line balance assembly. There is very l i ttle drop in rec eiver (handset earpi ece) vo l ume le vel d ue
to system cable losses. Generally, the only reason to reset the receiver volume control is to compensate
for extremely high ambient noise levels (up to 110 dB) or to meet particular personnel needs.

At stations with cable lengths of 3,000 feet (1 km) or more from the line balance assembly, receiver
sidetone rejection is noticeably affected by cable impedance. Use the receiver sidetone control to
compensate for this by rotating the control clockwise approximately 60 degrees for 3,000 feet (1 km) of
cable length.

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Step 7 — Troubleshooting the System

Hum or Buzz

Hum or buzz on the page circuit (or one or more party circuits) is usually due to either a short circuit of
one of the two conductors for each circuit to ground or unbalanced leakage to ground. As long as both
conduct ors are twisted pairs and t here are no significant leaka ge paths or short circ uits to ground, any
included voltages are the same on both conductors and do not appear across the line.

To correct the problem, locate the source of the ground. Using an ohmmeter, check various junction
point s of the system w irin g to deter mi n e in wh ich direct ion the grou nd can be locate d. Locate th e ground
by going from one junction point to another and disconnecting the affected circuit. The fault could be
within a plug-in amplifier. However, most ground circuits occur in improper terminations or are caused
by small strands protruding from an improperly lugged wire.

Another sour c e of grou nds or n ear- grounded c i rcuits is junction boxes f illed or partially-fill e d with water .
In many cases, there are deposits in the boxes, which, when combined with water, produce conductive or
corrosive solutions. These deposits cause leakage between circuits and can corrode the wire and
terminals.

Isolation of field wiring may be necessary for test purposes. If such isolation removes the line balance
assembly from the operating portion of the system, connect a 33-ohm, 0.5-watt resistor across L1 and L2
of the Page/Party

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line circuits. Remove these resistors after completion of the tests.

Feedback or Dis tortion on the System

Each page and party circuit must be loaded to the optimum 33 ohms using the line balance assembly. If
the line balance is not connected, or is defective, the system will have excessive gain and will break into
feedback quite easily. Speech will also be distorted, and there will be a high level of sidetone in the
handset receiver.

Each party line is terminated with fixed 33-ohm resistor in the line balance assembly. However, an
adjustable control is provided for the page line to compensate for the number of speaker amplifiers
connected to the system. Improper adjustment will affect gain and increase the level of sidetone. Please
refer to specific instructions above for adjusting the line balance assembly.

Very Low A udio Level on One or M ore Lines at all Stations

It is possible for the system, or part of the system, to function with a dead short across the page or party
circuits. If this occurs, the level of the system will be very low, decreasing to minimum level in the
vicinity of the short circuit. Locate the short circuit in the same manner as locating a ground, by checking
junction p oints wit h an ohmme ter.

Cross Talk

Cross talk, or interference, is generally caused by accidental crossing of circuits in a junction box. To
check for this condition, measure resistance between circuits of the interfering channels. The resistance
shou ld be i nfin ite or a very h igh va lue. L eaka ge or shorts to ground i n two or mor e c ircuits c an res ult in
cross talk on those circuits.

In a mu lti-pa rty l ine system, it is possible to ha ve a small am ount of c ross talk between cha nnels if line
balance resistors are opened or not connected. This condition can be detected by the presence of high
sidetone in the handset.

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In many normal installations, a static ac voltage may be read from the conductors of the page and party
line circuits to ground. In many cases this voltage may be as high as 50 volts or more. This voltage is
induced into the circuits by capacitance to the ac power circuit (generally carried in the same cable, and
also f rom power cables p aralleli ng comm unication c ables ) . This voltage is inconsequent ial and can be
ignored. Problems would only occur if one side of the page or party circuit becomes grounded.

Audio Voltag e

In a properly operating system, audio voltage read across any of the page or party circuits (L1 or L2) is

0.5 to 0.75 volts ac on peaks when an audio signal is present: i.e., someone speaking into a handset. The
voltage is proportional to the loudness of the person’s voice using the handset.

One Inopera tive Station in a Working Sys tem

Except for a wiring error, an inoperative station indicates a defect in the amplifier at the station. This is
checked quickly by installing a spare amplifier or exchanging amplifiers with a properly operating station.

Special Note Regarding Installation

GAI-Tr on ic s Cor poration Page/Party® system equipment does not, in normal operation, p roduce ar c s,
sparks or heat that would ignite industrial gas es or dusts . Many standard GAI-Tonic s pr oducts are
approved by Factory Mu tual ( USA) a nd certifi e d by CS A ( Canada) for intend e d use i n specifi e d Division
2 areas if properly installed and maintained.

Pr oper instal latio n is def ined as (1 ) mounting and wir ing p er fac tory directions without u naut horized
modification and (2) following all requirements of the U.S. National Electric Code (NFPA - 70) or the
Canadian Electric Code (CSA Standard C22.1). Installers must be familiar with these codes and consult
them as required. The most applicable parts of the N.E.C. code are in articles 500-503. The most
applicable parts of the Canadian code are in Section 18. Some, but not all, significant points are:

1. Conduits in a C lass I, Division 2 a rea to or fr om a non-hazardous area or an adjacent Class I, D ivision

1 area must have approved seals in the boundary.

2. Conduits or ra ceways in a C la s s II, Divisi on 2 or Cla s s III area must have dust seals at entrances to

dust-ti ght equip m e nt a nd at b ounda ries to other areas unless such conduits or raceways are als o dust­tight.

3. Explosion-proof (Division 1) equipment may be installed in a Division 2 area but must have the same

conduit and cable seals as if installed in the corresponding Division 1 area.

4. Sealing of multi-conductor cables or conduits containing multi-conductor cables in Class I, Division 1

or 2 areas must be around each conductor of the cable - except where type MI cable is used.

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Safe Power Connection/Disconnection

In or der to sat i sfy Division 2 r equire me nts, equ ipment must not create ar c s or sparks during nor ma l
operation, when completely installed and powered. Installing or removing an amplifier or plugging in a
live enclosure is not normal operation and can create arcs. To guarantee safety, adhere to the following
cautionary note:

CAUTION

Do not inser t o r remove equip me nt from live enclosures, unl ess the area is known to be no n­hazardous at the time.

A separate power disconnect is highly recommenced. It can be installed and safely used in either of two
ways:

1. An explosion-proof disconnect switch can be located in the Division 2 area.

2. An ordinary disconnect switch can be located in a non-hazardous area (outside the Division 2 area).

Either method will allow the use of the switch at all times. Connect field wiring as detailed in
instructions for the same equipment mounted in non-hazardous areas.

Power Distribution Recommmendations

The ac input current for a 12-watt 700 Series Station (Handset/Speaker Amplifier or Speaker Amplifier)
is 0.46 amperes RMS at full power output (50 VA/27 watts) with 120 V ac line voltage. The 14 AWG
wire used for power distribution in standard GAI-Tronics cable is rated at 15 amperes. This limits the
number of speaker amp stations per ac feed to 32 units or less. System larger than 32 stations will require
breaking the ac power feed into different branches.

Voltage drop must a l so be ta ken into consid erat io n for long ca ble runs. The mini mum op erat ing voltage
for a GAI-Tronics station is 90V ac and the resistance of 14 AWG cable is 26.8 ohms per loop mile.
Contact your nearest GAI-Tronics representative it you require assistance with system layout.

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