LG GHX-308A/616 Assembly instructions

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HYBRID KEY TELEPHONE
SYSTEM
INSTALLATION AND
PROGRAMMING MANUAL
MODEL : GHX - 308A/616
LG Electronics Inc.

GHX -308A/616
HYBRID KEY TELEPHONE SYSTEM
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REVISION HISTORY
ISSUE DATE DESCRIPTION OF CHANGES S/W VERSION
ISSUE 1.0A 1997.11 Initial Release 1.0A

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TABLE OF CONTENTS
SECTION 1. INTRODUCTION
1.1 PURPOSE ................................................................................................................ 7
1.2 REGULATORY INFORMATION ................................................................................ 7
SECTION 2. GEN ERAL DESCRIPTION
2.1 INTRODUCTION ...................................................................................................... 9
2.2 SYSTEM DESCRIPTION ......................................................................................... 9
2.3 SYSTEM CAPACITY ............................................................................................... 9
2.4 SYSTEM SPECIFICATION ....................................................................................... 10
2.5 EQUIP MENT DESCRIPTION .................................................................................... 11
2.6 KEY TELEPHONES & TERMINALS ......................................................................... 12
SECTION 3. INSTALLATION
3.1 SITE PL ANNING ........................................................................................................ 13
3.2 VERIFY ON- SITE EQUIPMENT ................................................................................. 13
3.3 KSU MOUNTING ...... ................................................................................................. 14
3.4 POWER VOLTAGE SELECTION ............................................................................... 15
3.5 KSU GROUNDING ...................... .............................................................................. 15
3.6 POWER LINE SURGE PROTECTION ....................................................................... 15
3.7 UNCOVERING THE KSU ........................................ ................................................... 16
3.8 MULTI FUNCTION UNIT(MFU) INSTALLATION ........................................................ 17
3.9 CO/PABX CONNECTIONS ....................................................................... ................. 17
3.10 KEY TELEPHONE/SLT CONNECTIONS ................................................................... 17
3.11 POWER FAILURE TRANSFER CONNECTION ......................................................... 19
3.12 PHONE BOX CONNECTION ..................................................................................... 19
3.13 LOUD BELL CONTROL CONNECTION .................................................................... 20
3.14 EXTERNAL PAGING CONNECTION ........................... ............................................. 20
3.15 BACKGROUND MUSIC AND MUSIC ON HOLD ....................................................... 20
3.16 HEADSET INSTALLATION ................................................................................ ....... 21
3.17 BATTERY BACK- UP INSTALLATION ....................................................................... 21
3.18 MEMORY BACK- UP SWITCH ................................................................................... 22
SECTION 4. FEATUR E DESCRIPTION
4.1 NUMBERING PLAN ..................................................................................................
Numbering Plan for GHX -308A ......................................................................................
Numbering Plan for GHX -616 ........................................................................................
Access Authorization Code (Password) .............................................................................
Account Cod e ...................................................................................................................
Alarm ....................................................................................................................... ........ .
Attendant ................................................................................................................... ........
Attendant Disable Outgoing CO Line Access ..........................................................
Attendan t Override .................................................................................................
Attendant Recall .....................................................................................................
Attendant Station Ass ignment .................................................................................
Automatic Pause Insertion with Speed Dial .........................................................................
Automatic Privacy .............................. .................................................................................
Automatic Selection ......................................................................................................... ...
Auto FAX Transfer ........................ .......................................................................................
Background Music ............................................................................................................ ...
Call Back ........................... ..................................................................................................
Call Forward ................................................................................................................ ........

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Call Park ............ ..................................................................................................................
Call Transfer ............................................................................................................... .........
Call Wait ........................................................................................................................ ......
CO Line Access ............................................................................................................ .......
CO Ring Assignment .......................................................................................................... ..
CO Ring Detect ........................................................................................................ ............
Conference .................................................................................................................. ........
Dial Sending ................................................................................................ ........................
Dialing Privileges (Class of Service) .......... ..........................................................................
Differential Ring Frequency Selection .................................................................... ................
DISA (Direct Inward System Access)......................................................................................
Do Not Disturb (DND) ................................................................................................ ............
Door Open Control ........................................................................................................... .....
DSS/DLS Box ................................................................................................... .....................
Emergency Transfer .......................................................................................................... ....
Executive/Secretary Transfer .......................................................................... .......................
Flash ....................................................................................................................... ..............
Flash with Speed Dial .................................................................... ........................................
Flexible Button Assignment .................................................................................................. ..
Flexible Station Number ............................................................ .............................................
Help ........................................................................................................................ ...............
Hold ............................................................... .....................................................................
Hot Line .................................................................................................................... ..........
Hunt Groups .................................... ....................................................................................
Intercom Signaling Select ................................................................................................... ...
Intercom Signaling Change .............. ......................................................................................
Intercom HOLD ............................................................................................................... ......
Intercom Transfer ................. .................................................................................................
Loop Button ................................................................................................................. .........
Loud Bell Control ... ...............................................................................................................
Message Display ............................................................................................................. .....
Custom Mess ages ...............................................................................................................
Pre - selected Messages . .......................................................................................................
Message Wait ......................................................................................................................
Monitor Mode (Group Listening) .............................................................................................
Musi c on Hold ................................................................................................................... ...
Mute ........................................................................................................................ ...........
Name Display ................................................................................................................ .......
Night Transfer ............................................................................................ ..........................
On - Hook Dialing ................................................................................................................ ...
Override ...................................................................................... ........................................
Page ........................................................................................................................ ...........
Paging .. ............................................................................................................................
Page Access Restriction ...................................................................................................
Meet Me Page ..................................................................................................................
Pause Timer ................................................................................................................. ........
PBX Dial Codes ................................................ ....................................................................
Phone Box ................................................................................................................... ........
Pickup ............................................ .....................................................................................
Directed Call Pickup ..........................................................................................................
Group Call Pickup .............................................................................................................
Branch Group ...................................................................................................................
Pool Button (CO Group Button) ....... .......................................................................................
Queuing ..................................................................................................................... .........
Queue Request ..................................................................................................................
Queue Recall .....................................................................................................................
Queue Cancel ....................................................................................................................
Redial ...................................................................................................................... ........... ..

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Ringin g Line Preference ........................................................................................................
Speed Dial .................................................................................................................. .........
Station Speed Dial ............................................................................................................
System Speed Dial ...........................................................................................................
Time Display ............................................................................................................... .......
Universal Night Answer (UNA) ........................................................................................ ......
Version Display ............................................................................................................. .......
3 Minute Warning ................................................................................................ .................
SECTION 5. SYSTEM PROGRAMMING
5.1 PROGRAM CODES LIST FOR GHX- 308A........................................................................
5.2 PROGRAM CODES LIST FOR GHX- 616.......................................................... ................
5.3 PROGRAM MODE ENTRY ..............................................................................................
5.4 INITIALIZATION .................................................................................................. .............
5.5 SYSTEM PARAMETER PROGRAMMING ........................................................................
System Hold Recall Timer (FLASH 01) ..............................................................................
Exclusive Hold R ecall Timer (FLASH 02) ...........................................................................
Transfer Recall Timer (FLASH 03) .....................................................................................
Preset Forward Timer (FLASH 04) . .....................................................................................
Pause Timer (FLASH 05) ....................................................................................................
Call Park Recall Timer (FLASH 06) ........ .............................................................................
Conference Timer (FLASH 07) ............................................................................................
Message Wait Reminder Tone Timer (FLASH 08) ......... ......................................................
CO Ring Detect Timer (FLASH 10) ......................................................................................
Hold Preference (FLASH 11) ................................................... ............................................
Automatic Privacy (FLASH 12) ............................................................................................
Attendant Call Code (0) (FLASH 13) .................................................. ..................................
Incoming CO Toll Restriction (FLASH 14) .........................................................................
Attendant Station Assignment (FLASH 15) .............................................................. ............
Loud Bell Control (FLASH 16) ..............................................................................................
PBX Access Codes (FLASH 17) ....................................................................................... ...
Executive/Secretary Transfer (FLASH 18) ...........................................................................
Hunt Group (FLASH 19) ......................................................................................................
SMDR ( FLASH 20, GHX - 616).................................................................................................
Alarm Detect & Signaling (FLASH 21, GHX - 616).....................................................................
PBX Calling Signal (FLASH 21, GHX - 308A) .........................................................................
Page Warning Tone (FLASH 22) ..........................................................................................
Program Control Relay (FLASH 23) .......... ...........................................................................
Phone Box Call Timer (FLASH 25) .......................................................................................
Setting Time and Date (FLASH 28) ..................... ..................................................................
Group Listening (FLASH 29) ................................................................................................
CO Line Programming (FLASH 30) .............................. .........................................................
Hook Flash Timer (FLASH 31) .............................................................................................
Attendant Recall Timer (FLASH 33) ..................................... .................................................
Incoming CO Ring Assignment to Hunt Group (FLASH 34, GHX- 616 ) ................................
Ring Type Selection (FLASH 35) ............................................................................ ..............
Flexible Station Numbering (FLASH 36) .................................................................................
Method of Seizing CO Line (FLASH 37) ............................................................................... ..
Multi -Line Conference (FLASH 39) ........................................................................................
Station Programming - (I) (FLASH 40) ...................................................................................
Off -net Forward CO to CO (FLASH 41, GHX- 616).....................................................................
Call Metering Unit (FLASH 42,GHX- 616)...................................................................................
Pre - selec ted Message Selection (FLASH 43, GHX- 616)............................................................
Call Forward No Answer Timer (FLASH 44, GHX- 616)..............................................................
Prevent Illegal Dial (FLASH 45) ... ............................................................................................
CO Dial Wait Timer (FLASH 46) ...........................................................................................
Exception Tables Programming (FLASH 5 0) ..............................................................................

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Music Source Control (FLASH 51)............................................................................................
Station Programming - (II) (FLASH 52) .... ..............................................................................
Hot Line (FLASH 53) ........................................................................................................ .. ...
Door Open Timer (FLASH 54) ............... .................................................................................
VAU Mode Program (FLASH 55, GHX- 616) .........................................................................
CO Dial Delay Timer (FLASH 56) .............................. ............................................................
Hot Line Timer (FLASH 57) ...................................................................................................
VAU Segment Control (FLASH 58,GHX- 616)...................... ...................................................
VAU Channel Control (FLASH 59, GHX- 616).........................................................................
Initialization (FLASH 60- 65) ....................................................... ...........................................
Initialize System Parameter (FLASH 60)................................................................................
Initialize CO Line Attribute (FLASH 61) ......................................... ...........................................
Initialize Station Attribute (FLASH 62) ..................................................................................... .
Initialize Exception Tables (FLASH 63) .................................... .................................................
Initialize System Speed Dial (FLASH 64) ..................................................................................
Initialize All Database (FLASH 65) ...................................... ......................................................
Print All Database (FLASH 70, GHX- 616) ..............................................................................
Print System Parameters (FLASH 71, GHX- 616) ........................... .........................................
Print CO Line Attributes (FLASH 72, GHX- 616) ......................................................................
Print Station Attributes (FLASH 73, GHX- 616) ......................................... ...............................
Print Exception Tables (FLASH 74, GHX- 616) ........................................................................
Print System Speed Numbers (FLASH 75, GHX- 616) ................................................. ............
Fax CO, Station Assignment (FLASH 76, GHX- 308A) ...........................................................
UCD Member First Choice (FLASH 76, GHX- 616) .................................................................
Fax Tone Dete ct Timer (FLASH 77, GHX- 308A) ...................................................................
DISA, with Hunt Group (FLASH 77, GHX- 616) ......................................................................
Fax CO Call Timer (FLASH 78, GHX- 308A) ..........................................................................
DISA Night Act (FLASH 78, GHX- 616 ) .................................................................................
SLT Ring Off Time (FLASH 79, GHX- 308A) ... .......................................................................
DISA Busy /No/Error Destination (FLASH 79, GHX - 616).......................................................... .
VAU Tone Cadence (FLASH 83, GHX- 616) ...................... .....................................................
VAU Tone Time (FLASH 84, GHX- 616) .................................................................................
DISA Message Replay (FLASH 85, GHX - 616) ................................... .......................................
Fax CO, Station Assignment (FLASH 86, GHX- 616)................................................................
Fax Tone Detect Timer (FLASH 87, GHX- 616).................................................. ......................
Fax CO Call Timer (FLASH 88, GHX- 616) .............................................................................
SLT Ring Off Time (FLASH 89, GHX- 616) ................................................................. ............

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SECTION 1. INTRODUCTION
1.1 PURPOSE
This manual provides the information necessary to configure, install, operate and maintain the GHX-308A Hybrid Key
Telephone System.
1.2 REGULATORY INFORMATION
A. TELCO NOTIF ICATION
Before connecting the GHX-308A Hybrid Key Telephone System to the telephone network, the local serving
telephone company must be given advance notice of intention to use customer provided equipment(CPE) and
provided with the information of the tel ephone numbers to be connected to the system.
B. INCIDENCE OF HARM
If the telephone company determines that the customer provided equipment(CPE) is faulty and possibly causing
harm or interruption to the telephone network, it should be disconnected until repair can be effected. If this is not
done, the telephone company may temporarily disconnected service.
C. CHANGES IN SERVICE
The local serving telephone company may make change in communications facilities or procedures. If these
changes should affect the use of GHX-308A or compatibility with the network, the serving telephone company must
give written notice to the user to allow uninterrupted service.
D. MAINTENANCE LIMITATION
Maintenance on the GHX-308A Hybrid Key Telephone System is performed only by the manufacturer or its
authorized agent. The user may not make any changes and/or repairs except as specifically noted in the manual. If
unauthorized alterations or repairs are performed, any remaining warranty may be voided.
E. NOTICE OF COMPLI ANCE
The GHX-308A Hybrid Key Telephone is designed to comply with rules regarding radiation and radio frequency
emission by class A computing devices. In accordance with FCC Standard 15(Subpart J), the following information
must be supplied to the end use r:
“ WARNING:
This equipment generates and uses R. F. energy, and if not installed and used in accordance with the instruction
manual, it may cause interference to radio communications.
It has been tested and found to comply with the limits for a Class A computing device, pursuant to Subpart J or Part
15 or the FCC Rules, which are designed to provide reasonable protection against such interference, when operated
in a commercial environment.
Operation of this equipment in residential area could cause in terference, in which case the user, at his own expense,
will be required to take whatever measures may be required to correct the interference.”
F. HEARING AID COMPATIBILITY
The GHX-308A Hybrid Key Telephone is Hearing Aid Compatible, as defined in Section 68.316 of Part 68 FCC
Rules.

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SECTION 2. GENERAL DESCRIPTION
2.1 INTRODUCTION
The GHX-308A Hybrid Key Telephone System is designed to meet the telecommunication needs of small size business
using maximum 3 CO lines & 8 extensions.
The system is a flat pack system equipped with basic 3 CO lines and 8 extensions (KTU : 1, Hybrid : 3, SLT : 4).
2.2 SYSTEM DESCRIPTION
The GHX-308A Hybrid Key Telephone System is microprocessor controlled, solid state electoric switching system. All
controls, switching and interface circuitry are condensed onto a single printed circuit board(PCB) located inside the key
service unit(KSU). The system can support both key telephone and single line telephone of DTMF and dial pulse type.
Switc hing is accomplished through a solid state crosspoint matrix that provides voice path connections for 3 Central
Office lines, 1 Key Telephone, 3 Hybrids (Key telephone or SLT), and 4 SLTs.
There are two(2) external control contact ports that can be flexibly assigned to use loud bell control, external paging
control, door open control and music on hold control.
The system also provides a battery backup interface circuit and a connector that allows customer provided external
battery to be connected with the system, with this facility the system can execute its normal operation during commercial
power failure.

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The GHX-308A contains all system memories, which composed of 128Kbyte of ROM and 32Kbyte of RAM. The RAM is
subdivided so that part is used as CPU working area and part is used for customer database. The customer database
memory is protected from loss by a long-life lithium battery. The system generic memory(ROM) is mounted in the IC
socket on the MBU. This allows easy access for removal of system softw are when upgrading software feature package.
2.3 SYSTEM CAPACITY
A. CONFIGURATION FOR OUTSIDE AND INTERNAL LINES
Description System Capacity Max. Capacity
CO/PABX 3 3 Lines
Key Telephone 1 2 3 4 8 Lines
Single Line Telephone 7 6 5 4
B. OTHE R SYSTEM SOURCES
4 Intercom channels
1 Music source input
2 Free relay contacts
2 Power failure transfer ports
2.4 SYSTEM SPECIFICATION
A. ELECTRICAL SPECIFICATIONS
AC Input
Power Consumption
Output Voltage
Station Cable Lengths (Maximum)
(Twis ted 2 pair)
110 or 220 VAC ± 10%, 50~60Hz
60Watts
28V DC ± 10%, 1.6A
150m. of 26AWG Cable
300m. of 24AWG Cable
450m. of 22AWG Cable
Fuse - AC Input 110V : T500mA/250V
220V : T315mA/250V
Music Source (Input) 600 Ohms at 0 dBm
Contact R ating
External Page Control
Loud Bell Control
1.0A, 24VDC
1.0A, 24VDC
External Page Port
Output Impedance
Output Power
600 Ohms at 0dBm
1mW maximum
B. ENVIRONMENTAL SPECIFICATIONS
Operation Temperature
Recommended Temperature
0~50 ?
20~26 ?
Humidit y 5- 85 % (non - condensing)
C. DIALING SPECIFICATIONS

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DTMF DIALING
Frequency Deviation
Rise Time
Duration of DTMF Signal
Interdigit Time
less than ± 1%
3 msec.
100 msec. minimum
100 msec. minimum
DIALING MEMORY
System Speed Dialing
Station Speed Dialin g
80 numbers (24 digits)
20 numbers per station (24 digits)
OUTSIDE LINE TYPE
Loop start
D. DIMENSIONS AND WEIGHTS
BASIC KEY SERVICE UNIT
Height
Width
Depth
Weight
37.5cm (14.7 inches)
27.2cm (10.8 inches)
6.7cm (2.6 inches)
KEY TELEPHONE (GSX - 33 EXE)
Height
Width
Depth
Weight
22cm (8.75 inches)
22cm (8.85 inches)
7cm (2.75 inches)
1.6Kg (4.4 lbs)
PHONE BOX (GSX - PHONE BOX)
Height
Width
Depth
Weight
4.5cm (1.75 inches)
14cm (5.5 inches)
10cm (4 inches)
0.5Kg (1 lbs)
2.5 EQUIPMENT DESCRIPT ION
A. KEY SERVICE UNIT (KSU)
The KSU is a self-contained unit that contains the power supply, processor, external connectors and circuits for 4
CO lines and 8 extension lines. External connections use screw terminal connections. The KSU, is a metal fra me
cabinet for wall mounting. The KSU contains Main Board Unit(MBU) and power transformer.
The MBU contains;
- Micro Processor & Control Circuitry
- 3 CO(outside) lines
- 1 Analogue Keyset Interface
- 3 Hybrid (Keyset or SLT) Interfaces
- 4 Single Line Telephone(SLT) Interfaces
- 1 Real Time Clock
- 1 Internal Music Source
- 1 DTMF Generator
- 2 DTMF Receivers
- 2 Emergency Transfer Ports
- 1 Ring Generator
- 1 External Control Contact Relay
B. MULTI FUNCTION UNIT ( MFU) : Option
The MFU can be installed optionally on the MBU. The MFU contains :

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- 1 Fax. Tone Detect Circuit
- 1 External Music Source
- 1 External Paging
- 1 External Control Contact Relay
2.6 KEY TELEPHONES & TERMINALS
There are 3 seri es of electronic terminal to be used with GHX - 308A as follows;
A. GSX Series
- GSX 21EXE, GSX 33EXE : Display Type
- GSX 21ENH, GSX 33ENH : Non- Display Type
- GSX 8BTN (With SPU)
B. GSX/E Series
- GSX/E 21EXE, GSX/E 33EXE : Display Type
- GSX/E 21ENH, GSX/E 33ENH : Non- Display Type
- GSX/E 8BTN (With SPU)
C. GK Series
- GK - 24E, GK -36E : Display Type
- GK - 24S, GK -36S : Non- Display Type
- GK - 8S (With SPU)
D. OTHERS
- PHONE BOX
SECTION 3. INSTALLATION
3.1 SITE PLANNING
The first step is to locate an acceptable site for the common equipment (KSUs, boards, etc.). When locating a mountion
site for the KSUs, the following points must be considered;
a) The KSUs are designed for wall- mounting and should n ot be mounted directly to a

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masonry or plaster - board wall. It is recommended that 1/2 inch polywood back - board
be firmly mounted to the wall.
b) The location must have access to a dedicated 110 Volt AC or 220 Volt AC, 50-60Hz circuit with a circuit br eaker
or fuse rated at 2amps. A 3 - wire parallel blade grounded outlet should be within approximately 2 meters(6 feet)
of the lower left rear of the BKSU mounting.
c) The location have access to a good earth ground, such as a metallic cold water pipe with
non - metallic joints. The ground source should be located as close as possible to the
system.
d) The system should be located in an area which is well ventilated with a recommended
temperature of 20 - 26 ? (68 - 78.8 ? ) and a relative humidity of 5~85%(non - con densing).
e) The system should be located within 8 meters(25 feets) of the telephone company’s termination point. Also, the
location should be within the prescribed station loop lengths for all keysets and terminals. If exiting cabling is to
be employed, the location of existing cabling and conduits should be considered.
f) The location should have adequate accessibility, space and lighting for future servicing and should consider the
need for future expansion.
g) The site should be away from radio transmitting equipment, arc-welding devices, copy machines, and other
electrical equipment capable of generating electrical interference. The system should be protected from
flooding and heavy machinery as well as excessive dust and vibration.
3.2 VERIFY ON- SITE EQUIPMENT
Once the equipment installation site has been identified and a dedicated AC outlet, earth-ground, and lighting and
ventilation are available, verify that all equipments required are on-site and has not been damaged during shipment.
Unpack the KSUs assure there is no shipping damage. Note that a mounting template is packed with KSU and this
template will be required later in the installation.
Check that type and quantity of boards received is correct and optional equipment and a Power Line Surge Protector are
on - site. Note that the individual boards should not be unpacked at this time.
If any equipment is damaged or missing, notify appropriate personnel to correct the situation.

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3.3 KSU MOUNTING
Employing the KSU mounting template provided with the KSU, mark the location of the two screws to mount the KSU.
Again, the KSU must not be mounted on a masonry or dry - wall surface.
The KSU is mounted with four #10 or larger, 1 1/2 inch or long screws. Drill pilot holes in the two locations marked, insert
the screws and tighten leaving about 1/2 inch exposed. Mount the KSU on the screws and tighten the screws securely.
6.4
7
f 10
LEFT
WALL SIDE K S U
[Figure 3 -1] KSU MOUNTING
3.4 POWER VOLTAGE S ELECTION
The power of system is used 110VAC or 220VAC, 50~60Hz. When the system is shipped, the power voltage selection in
the inside of the KSU is set to 220 VAC at factory. If you use 110VAC, the primary connector of power transformer
should be moved “ CN220” to “CN110” position.

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3.5 KSU GROUNDING
To ensure proper system operation and for safety purposes, a good ground is required. A metallic COLD water pipe
usually provides a reliable ground. Carefully check that the pipe does not contain insulated joints that could isolate the
ground path. If insulated joints exist, another earth ground source must be used or, if allowed, the joints may be bridged.
A #14 AWG or larger copper wire should be used between the ground source and the KSU. The
wire shou ld be kept as short as possible, it is recommended that the wire be no longer that 8 meters(about 25 feets).
3.6 POWER LINE SURGE PROTECTION
The GHX-308A Hybrid Key Telephone System should be equipped with a power-line transient surge protection device.
System equipped with such devices are more resistant to damage from power line surge than unprotected systems.
Power line surges often occur during switching operations and especially during violent thunderstorm activity.
Installation if a surge protector meeting the specifications described in the following paragraph with prevent or minimize
the damage resulting from power - line surges.
The surge protector shall be a 15 amp self-contained unit that plugs into a standard, grounded 110/220VAC wall oulet .
The wall outlet must be designed to accept a 3-prong plug(2 parallel blades and group pin). The protector should be fast
operating and capable of protecting for transients greater than 220/400 volts.
The AC power cord should not be plugged in at this ti me.

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3.7 UNCOVERING THE KSU
The below figure is the inside of KSU, GHX - 308A.
ON
CN224
OFF
CN227 M F U CN226
INT EXT
CN225
BATT.
S/W K/P
CN102
SLT
K/P
CN101 K/P
CN103
SLT SLT
CN229
F2 CN230
CN228
F1
CN220
CN110
POW ER RING
TRANSFORMER TRANS
CN221 F4
[Figure 3 -2] Inside of KSU
Note 1) ■ : State of Short Pin
2) BATT.S/W : Only with BBU
3.8 MULTI FUNCT ION UNIT(MFU) INSTALLATION

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A. Before installing the MFU, turn off the power of system.
B. Insert carefully the MFU to connector “CN226” and “CN227” on the MBU.
MFU
Insert
MBU
CN227 CN226
[Figure 3 -3] MFU INSTALLATION
C. After installing MFU, program the followings;
a) Assign the CO & the extension port for FAX. (FLASH 76)
b) Assign the detect timing of FAX tone. (FLASH 77)
3.9 CO/PABX CONNECTIONS
All CO/PABX line connections are made on the connector CO 1T/1R ~ 3T/3R.
CO/PABX lines are connected to terminals CO #T and #R on the MDF.
*. FR : Free Relay
1T 1R 2T 2R 1T 1R 2T 2R 3T 3R MBU CO : Central Office
FR CO Line
LINE1 LINE2 LINE3
[Figure 3 -4] CO/PABX LINE CONNECTIONS
3.10 KEY TELEPHONE/SLT CONNECTIONS
A. KEY TELEPHONE UNIT
Maximum 4 Key Telephones can be installed with GHX - 308A Hybrid Key Telephone System.
Each Key Telephone requires 2-pair(4wires) twisted wiring cable be used to connect with MDF. The installer should
exercise caution when connecting a key telephone while system power on. The second pair(DT,DR) or wires supplies
the power (+30V) and the data. The first pair(VT,VR) supplies the power(GND) and the voice transmission. The power
polarity of wired connections must be maintained for proper operation. Care should be taken to ensure the telephones are
wired properly.
Color of Wires Contents MDF Terminal
Black
Yello w
Green
Red
Power (+) / Data Line
Power (+) / Data Line
Power ( - ) / Voice Line
Power ( - ) / Voice Line
DT#
DR#
VT#
VR#
a) Extension #100 is only the Key Telephone and connects to <DT,DR,VT,VR> terminals of
connector “K100” on the MBU.
b) Extension #10 1~103 are universal ports that SLT or Key Telephone can be connected by
user’s selection.

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In case of Key Telephone connection, the short pins of connector “CN101~103” on the MBU should be moved “SLT”
to “K/P” position and the Key Telephones connect to <DT,DR,VT,VR> terminals of connectors “K101~103” on the
MBU.
CN101 : Extension #101
CN102 : Extension #102 Universal port (KTU or SLT selection)
CN103 : Extension #103
K/P K/P *. ■ : State o f
Short Pin
SLT SLT
? Key Telephone ? ? Single Line Telephone ?
[Figure 3 -5] KEY/SINGLE LINE TELEPHONE SELECTION
VT VR DT DR VT VR DT DR T R T R
K100 K101 S101 S104
Key Key or SLT SLT
Telephone Telephone
? Only Key Telephone ? Key telephone / Single ? Single Line
port ? Line Telephone port ? Telephone ?
[Figure 3 -6] KEY/SINGLE LINE TELEPHONE WIRING
B. SINGLE LINE TELEPH ONE
Maximum 7 Single Line Telephones(Extension #101~107) can be installed with GHX-308A Hybrid Key Telephone
System.
a) Extension #101~103 are universal ports that SLT or Key Telephone can be connected by user’s
selection.
In case of Single Line Telephone connection, the short pins of connector “CN101~103” on the MBU should be moved
“K/P” to “SLT” position and the Single Line Telephones connect to <T, R> terminals of connectors “S101~103” on the
MBU.
b) Extension #104~107 have only used the Single Li ne Telephones and connected to <T, R>
terminals of connectors “S104~107” on the MBU.
3.11 POWER FAILURE TRANSFER CONNECTION

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In the event of a commercial power failure without battery back-up, upto 2 CO/PABX lines can be automatically
transferred to single line telephones for emergency communications. When power interrupted, CO 1T/R, 2T/R are
automatically transferred to SLT #106, #107, the corresponding emergency telephone can be used as SLT extension
under normal operation.
CO/PBX Line #1 ? Tran sfer to SLT #106 (Connector “S106 T/R” on the MBU)
CO/PBX Line #2 ? Transfer to SLT #107 (Connector “S107 T/R” on the MBU)
MBU
T R T R 1T 1R 2T 2R
S1 07 S107 CO
SLT SLT LINE1 LINE2
[Figure 3 -7] POWER FAILURE TRANSFER CONNECTIONS
3.12 PHONE BOX CONNECTION
The GSX Phone Box is designed to initiate calls to preassigned stations as well as receive intercom calls with handsfree
talkback operation.
The unit should be located in weather protected areas where paging or monitoring is required.
Each phone box is connected to a dedicated key telephone station line cord position.
The connection of Phone Box(es) to the KSU is identical to that of key telephone.
a) The housings separated by inserting a thin, flat-edged tool at the bottom rim of the assembly. By pressing inward
on the recessing tab, the assembly will op en.
b) The cable is routed through the cable entry holes provided on the bottom plate and is connected to the screw
terminal strip on the upper housing. Four screw terminals are identified by wire color on the silk - screened printed
circuit board to correcs pond with the wiring sequence at the MDF.
c) The slack wiring should be pulled back through the bottom mounting plate and the top housing snapped shut.
d) The bottom plate of the Phone Box assembly is fastened to the wall by mounting with NO.8 or larger pan head
screws.
3.13 LOUD BELL CONTROL CONNECTION
The GHX - 308A system provides relay contact closure to activate optional signaling equipment during incoming CO/PABX
line and intercom ringing.
The stations for Loud Bell Control are selected as part of system programming (Admin program, FLASH 23). Connect the
Loud Bell to FR 1T/1R, 2T/2R terminal of free relay on the MBU.
Regular electrical specification of the free relay is 120VAC, 500mA(24VDC 1A).
See [Figure 3 - 8] Miscellaneous Wiring .

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3.14 EXTERNA L PAGING CONNECTION
External paging amplifier equipment can be connected to the GHX - 308A system for external paging from any telephone.
The output impedance of the paging signal port is 600 ohm at 0 dBm.
The voice signal output is specified at 5mW maximum. Regular electrical specification of the relay is 120VAC 500mA
(24V DC 1A). For external paging contact control, the free relay (FR #T/#R) is provided to switch the external amplifier
equipment. The voice output is provided the E.PAGE T/R pair on the M BU. See [Figure 3 - 8] Miscellaneous Wiring .
3.15 BACKGROUND MUSIC AND MUSIC ON HOLD
Music - On -Hold as well as background music through telephone speaker can be connected to either KSU contained
music(Melody IC) or via a customer provided tuner, tape deck, etc., by setting music select pin of connector “CN225” on
the MBU.
When the system is shipped, the music select pin is set to internal music(Melody IC) at the factory. If you want to
connect external audio equipment, the music select pin of “CN225” should be moved “INT” to “EXT” - external music
position. See [Figure 3 - 8] Miscellaneous Wiring .
T R T R 1T 1R 2T 2R
E.PAGE MOH FR
Input Impedance
600ohm
Amplifier External Music
Source Ringer
Customer Pr ovided
Power control of ext. amplifier DC Voltage Source
Note) E. PAGE : External Paging Port
FR : Free Relay Port
MOH : Music On Hold Port
[Figure 3 -8] MISCELLANEOUS WIRING
3.16 HEADSET INSTALLATION
The Key Telephone has been designed to operate with industry standard modular headset adapters and operator
headsets. To modify a key telephone to support an external headset, plug the headset adapter cord into handset jack on
the key telephone base. Plug the telephone handset cord into the headset adapter box where indicated by the headset
manu - facturer’s instructions.
In the Admin program FLASH 40, speakerphone operation must be disabled to allow headset operation. When this is
done, such features as On- Hoo k Dialing and Handsfree speakerphone operation are rendered inoperable. However,
incoming page/voice announcements, tone ringing and background music will still be heard over the keyset speaker.
The monitor key(MON) then controls the on - hook or off - hook st atus of the telephones.

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3.17 BATTERY INSTALLATION
A separate external 24 Volt DC battery package must be provided and selected to ensure the proper back-up time during
power outage. 24 VDC(normally two 12 VDC batteries) package with a 20 Ampere hour ra ting is considered maximum.
It is recommended that maintenance-free gel-type batteries be used. The following must be considered when connecting
batteries.
A. Batteries are to be placed in a limited access room or cabinet with adequate ventilation to dissipate any battery gases
that may be present.
B. The batteries are to be installed in accordance with Article 480 of the National Electrical Code (NEC) in U.S.A. or any
other applicable codes.
C. A battery rack or case should be used to secure the batteries to prevent tipping or any movement that could cause
spilling of battery acid or shorting of terminals.
The arrangement should protect against all hazards such as fire, spark, heat, gas fumes and accidents.
D. Use the shortest length of flexible cord type that will comply with the National Electrical Code to connect batteries and
the KSU. The cable should be located, routed and clamped(strain relief) in such a way as to prevent the batteries
from moving should the cables be moved.
E. A 12 Amp 32V mininmum fuse or a 12 Amp DC instantaneous tripping circuit breaker should be installed. Locate it at
batteries “in line” with the battery negative lead to protect the battery from damage.
F. See [Figure 3- 9] for wiring considerations. DC input wire size should be sufficient to restrict voltage drop to 0.5 volt or
less at rated input current between the battery and the KSU. The loop length is the sum of the lengths of the negative
and positive leads. Use wire sizes recommended by the National Electrical Code and/o r local regulations.
(CN230 : External Battery Terminal)
CN230
MBU
FUSE
(5A/250V)
12VDC 12VDC
[Figure 3 -9] BATTERY CONNECTION
3.18 MEMORY BACK- UP SWITCH
To protect the user database from being lost during System power failure, the short pin of connector “CN224” on the
MBU should be moved “OFF” to “ON” position after Admin programming. (refer to Figure 3 -2)