Sonifex DHY-04G User manual

Manufacturers of audio & video
products for radio & TV broadcasters
HANDBOOK
DHY-04G GSM TBU
DHY-04G
DHY-04GS
DHY-04GT
Single Freestanding Automatic GSM Hybrid, AES/EBU &
Analogue I/O With Ethernet
Single Rackmount Automatic GSM Hybrid, AES/EBU &
Analogue I/O With Ethernet
Twin Rackmount Automatic GSM Hybrid, AES/EBU &
Analogue I/O With Ethernet
DHY-04HD HD Voice Hybrid
DHY-04HD
DHY-04HDS
DHY-04HDT
Single Freestanding Automatic HD Voice Hybrid,
AES/EBU & Analogue I/O With Ethernet
Single Rackmount Automatic HD Voice Hybrid,
AES/EBU & Analogue I/O With Ethernet
Twin Rackmount Automatic HD Voice Hybrid,
AES/EBU & Analogue I/O With Ethernet
HD Voice Hybrid

DHY-04G & DHY-04 HD Handbook
Made in the UK by
This handbook is for use with the following product:
DHY-04G Single Freestanding Automatic GSM Hybrid, AES/EBU & Analogue I/O With Ethernet
DHY-04GS Single Rackmount Automatic GSM Hybrid, AES/EBU & Analogue I/O With Ethernet
DHY-04GT Twin Rackmount Automatic GSM Hybrid, AES/EBU & Analogue I/O With Ethernet
DHY-04HD Single Automatic HD Voice Hybrid, AES/EBU & Analogue I/O With Ethernet
DHY-04HDS Single Rackmount Automatic HD Voice Hybrid, AES/EBU & Analogue I/O With Ethernet
DHY-04HDT Twin Rackmount Automatic HD Voice Hybrid, AES/EBU & Analogue I/O With Ethernet
©Sonifex Ltd, 2016
All Rights Reserved
Revision 1.04, October 2016
Sonifex Ltd, 61, Station Road, Irthlingborough,
Northants, NN9 5QE, England.
Tel: [phone]
Fax: [phone]
Email: [email protected]o.uk
Website: http://www.sonifex.co.uk
Information in this document is subject to change without notice and does not represent a
commitment on the part of the vendor. Sonifex Ltd shall not be liable for any loss or damage
whatsoever arising from the use of information or any error contained in this manual.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic
or mechanical, including photocopying, recording, information storage and retrieval systems, for any
purpose other than the purchaser’s personal use, without the express written permission of Sonifex
Ltd. Unless otherwise noted, all names of companies, products and persons contained herein are part
of a completely fictitious adaptation and are designed solely to document the use of Sonifex product.

Contents
Contents
Product Warranty - 2 Year Extended i
Sonifex Warranty & Liability Terms & Conditions i
1. Definitions i
2. Warranty i
Unpacking Your Product ii
Repairs & Returns iii
Conformity iii
Safety & Installation of Mains Operated Equipment iii
Voltage Setting Checks iii
Fuse Rating iii
Power Cable & Connection iii
WEEE Directive iv
Atmosphere/Environment iv
1 What Is A Telephone Hybrid? 1
DHY-04G Single Automatic GSM Hybrid, AES/EBU
& Analogue I/O With Ethernet 1
DHY-04G Single Freestanding Automatic GSM Hybrid 2
DHY-04GS Single Rackmount Automatic GSM Hybrid 3
DHY-04GT Twin Rackmount Automatic Digital TBU 3
DHY-04HD Single Automatic HD Voice Hybrid, AES/EBU &
Analogue I/O With Ethernet 4
DHY-04HD Single Freestanding Automatic HD Voice Hybrid 5
2 Configuration & Controls - DHY-04G, DHY-04HD 6
Front Panel Controls 6
Power LED Indicator 6
Reset Button 6
Speed Dial Buttons 6
AES/EBU Lock LED 6
Line Hold/Connect Button 6
Gain Switches (Level To & From The Line) 6
LED Bargraphs & Signal Strength Indicator 7
Network LED 7
SIM Enabled LED 7
Signal Strength Button 7
Status & Operating Mode Information 7
DHY-04G/HD Internal Controls & Adjustments 7
Jumper and Select Switcher Functions 7
Rear Panel Controls & Connections 8
AES/EBU & Analogue Combined Line Output 8
Mic/Line & AES/EBU Input 8
Mic/Line Input Select Switch 8
Adjusting the Microphone Gain Level 8
Remotes 8
Conference Audio/Record Output 8
GSM Antenna 9
SIM Card Slot 9
RS232 Serial Port 9
Ethernet Port 9
Mains Input 10
Protective Earth Terminal 10
Configuration Settings DIPSwitches 10
3 Connecting the DHY-04G/HD TBU 11
IEC Mains 11
GSM Antenna 11
Remote Line Hold 11
Mic/Line Input 11
XLR Output 11
Using The AES/EBU Input & Output 12
Using the DHY-04G/HD 12
Call Established 12
Using the Conference Port as a Record Output 13
Using the Conference Port to Share a Stereo Digital Audio
Connection between Two DHY-04G/HD Units 13
4 Hybrid Technical Description 14
Echo Cancellation 14
5 Serial Port Control 15
DHY-04G/HD Serial Connection 15
SCI Software 15
Serial Interface Commands & Responses 15
Error Messages 15
6. Webserver & Network Discovery 16
Connecting to the Device 16
First Time Usage 16
MDNS-SD and Bonjour 16
Sonifex Service Discovery App 16
Home Page 18
Status 18
Line 18
Dial 18

Contents
Call State 19
Dial 19
Configuration 20
Config Name 20
Description 20
Echo Duration 20
Local Number 20
Conference Port Function 20
Force Analogue Output 21
Answer Control 21
Submit Button 21
Remote Input Port 21
Remote Output Port 21
Password Setting 23
Network Settings 24
Bonjour Name 24
Static IP Address 24
Static Subnet Mask 25
Gateway IP Address 25
Dynamic Addressing 25
Device Info Page 26
Update Firmware Page 27
Update Firmware 27
Update GSM Module 28
Update Config Files 28
Log In 29
Bootstrap Mode 30
7 Technical Specification DHY-04G, DHY-04HD 31

Figures
Figures
Figure 1-1: DHY-04G Front & Rear 2
Figure 1-2: DHY-04GS Front & Rear 3
Figure 1-3: DHY-04GT Front & Rear 3
Figure 1-4: DHY-04HD Front & Rear 5
Figure 2-1: Front Panel Controls 6
Figure 2-2: Internal Position of Jumper J1 7
Figure 2-3: Rear Panel Controls 9
Figure 2-4: Configuration Settings Switches 10
Figure 3-1: DHY-04G/HD User Connections 11
Figure 3-2: Conference Port Cable Connections 13
Figure 6-1: Bonjour Service Discovery Page 17
Figure 6-2: Legacy Service Discovery Page 17
Figure 6-3: Home Page 18
Figure 6-4: Dialler Page – simple screen for making calls
– accessed via Home Menu drop-down 19
Figure 6-5: Telephone Configuration
– selection of conference, auto answer & remote ports 20
Figure 6-6: Password Setting Page 23
Figure 6-7: Network Page – settings for network interface 24
Figure 6-8: Device Info Page
– shows info about the DHY-04G/HD product 26
Figure 6-9: Updates Page – to update the system
firmware and load/save configuration files 27
Figure 6-10: Log In Page 29
Figure 6-11: Bootstrap Page 30

Warranty Registration
Sonifex Limited y61 Station Road yIrthlingborough yNorthamptonshire yNN9 5QE yUnited Kingdom
Tel: [phone] yFax: [phone] yEmail: [email protected]o.uk yInternet: www.sonifex.co.uk
As standard, Sonifex products are supplied with a
1 year back to base warranty.
If you register the product online, you can increase
your product warranty to 2 years and we can
also keep you informed of any product design
improvements or modifications.
To register your product, please go online to
www.sonifex.co.uk/register
Register Online for an
Extended 2 Year Warranty
Product:
Serial No:

i
Warranty
Product Warranty - 2 Year Extended
As standard, Sonifex products are supplied with a 1 year back to base
warranty. In order to register the date of purchase and so that we can keep
you informed of any product design improvements or modifications, it is
important to complete the warranty registration online. Additionally, if you
register the product on the Sonifex website, you can increase your product
warranty to 2 years. Go to the Sonifex website at: http://www.sonifex.
co.uk/technical/register/index.asp to apply for your 2 year warranty.
Note: For your own records the product serial number is recorded on the
CE certification page of this handbook.
Sonifex Warranty & Liability Terms & Conditions
1. Definitions
‘the Company’ means Sonifex Ltd and where relevant includes companies
within the same group of companies as Sonifex Limited.
‘the Goods’ means the goods or any part thereof supplied by the Company
and where relevant includes: work carried out by the Company on items
supplied by the Purchaser; services supplied by the Company; and software
supplied by the Company.
‘the Purchaser’ means the person or organisation who buys or has agreed
to buy the Goods.
‘the Price’ means the Price of the Goods and any other charges incurred by
the Company in the supply of the Goods.
‘the Warranty Term’ is the length of the product warranty which is usually
12 months from the date of despatch; except when the product has been
registered at the Sonifex website when the Warranty Term is 24 months
from the date of despatch.
‘the Contract’ means the quotation, these Conditions of Sale and any
other document incorporated in a contract between the Company and the
Purchaser.
This is the entire Contract between the parties relating to the subject
matter hereof and may not be changed or terminated except in writing in
accordance with the provisions of this Contract. A reference to the consent,
acknowledgement, authority or agreement of the Company means in
writing and only by a director of the Company.
2. Warranty
a. The Company agrees to repair or (at its discretion) replace Goods
which are found to be defective (fair wear and tear excepted) and
which are returned to the Company within the Warranty Term
provided that each of the following are satisfied:
i. notification of any defect is given to the Company immediately
upon its becoming apparent to the Purchaser;
ii. the Goods have only been operated under normal operating
conditions and have only been subject to normal use (and
in particular the Goods must have been correctly connected
and must not have been subject to high voltage or to ionising
radiation and must not have been used contrary to the
Company’s technical recommendations);
iii. the Goods are returned to the Company’s premises at the
Purchaser’s expense;
iv. any Goods or parts of Goods replaced shall become the
property of the Company;
v. no work whatsoever (other than normal and proper
maintenance) has been carried out to the Goods or any part of
the Goods without the Company’s prior written consent;

ii
Warranty
vi. the defect has not arisen from a design made, furnished or
specified by the Purchaser;
vii. the Goods have been assembled or incorporated into other
goods only in accordance with any instructions issued by the
Company;
viii. the defect has not arisen from a design modified by the
Purchaser;
ix. the defect has not arisen from an item manufactured by
a person other than the Company. In respect of any item
manufactured by a person other than the Company, the
Purchaser shall only be entitled to the benefit of any warranty or
guarantee provided by such manufacturer to the Company.
b. In respect of computer software supplied by the Company the
Company does not warrant that the use of the software will be
uninterrupted or error free.
c. The Company accepts liability:
(i) for death or personal injury to the extent that it results from the
negligence of the Company, its employees (whilst in the course
of their employment) or its agents (in the course of the agency);
(ii) for any breach by the Company of any statutory undertaking as
to title, quiet possession and freedom from encumbrance.
c. Subject to conditions (a) and (c) from the time of despatch of
the Goods from the Company’s premises the Purchaser shall be
responsible for any defect in the Goods or loss, damage, nuisance
or interference whatsoever consequential economic or otherwise or
wastage of material resulting from or caused by or to the Goods. In
particular the Company shall not be liable for any loss of profits or
other economic losses. The Company accordingly excludes all liability
for the same.
e. At the request and expense of the Purchaser the Company will test
the Goods to ascertain performance levels and provide a report of
the results of that test. The report will be accurate at the time of the
test, to the best of the belief and knowledge of the Company, and the
Company accepts no liability in respect of its accuracy beyond that
set out in Condition (a).
f. Subject to Condition (e) no representation, condition, warranty or
other term, express or implied (by statute or otherwise) is given by
the Company that the Goods are of any particular quality or standard
or will enable the Purchaser to attain any particular performance
or result, or will be suitable for any particular purpose or use
under specific conditions or will provide any particular capacity,
notwithstanding that the requirement for such performance, result or
capacity or that such particular purpose or conditions may have been
known (or ought to have been known) to the Company, its employees
or agents.
g. (i) To the extent that the Company is held legally liable to the
Purchaser for any single breach of contract, tort, representation
or other act or default, the Company’s liability for the same
shall not exceed the price of the Goods.
(ii) The restriction of liability in Condition (g)(i) shall not apply to
any liability accepted by the Seller in Condition (c).
h. Where the Goods are sold under a consumer transaction (as defined
by the Consumer Transactions (Restrictions on Statements) Order
1976) the statutory rights of the Purchaser are not affected by these
Conditions of Sale.
Unpacking Your Product
Each product is shipped in protective packaging and should be inspected
for damage before use. If there is any transit damage take pictures of the
product packaging and notify the carrier immediately with all the relevant

iii
CE Conformity
details of the shipment. Packing materials should be kept for inspection and
also for if the product needs to be returned.
The product is shipped with the following equipment so please check to
ensure that you have all of the items below. If anything is missing, please
contact the supplier of your equipment immediately.
Item Quantity
Product unit 1
IEC mains lead fitted with moulded mains plug 1
Handbook and warranty card 1
GSM stubby antenna 1
If you require a different power lead, please let us know when ordering the
product.
Repairs & Returns
Please contact Sonifex or your supplier if you have any problems with your
Sonifex product. Email [e-mail] for the repair/
upgrade/returns procedure, or for support & questions regarding the
product operation.
Conformity
The products in this manual comply with the essential requirements of the
relevant European health, safety and environmental protection legislation.
The technical justification file for this product is available at Sonifex Ltd.
The declaration of conformity can be found at:
http://www.sonifex.co.uk/declarations
Safety & Installation of Mains
Operated Equipment
There are no user serviceable parts inside the equipment. If you should
ever need to look inside the unit, always disconnect the mains supply
before removing the equipment covers. The cover is connected to earth
by means of the fixing screws. It is essential to maintain this earth/
ground connection to ensure a safe operating environment and provide
electromagnetic shielding.
Voltage Setting Checks
Ensure that the machine operating voltage is correct for your mains power
supply by checking the box in which your product was supplied. The voltage
is shown on the box label. The available voltage settings are 115V, or 230V.
Please note that all products are either switchable between 115V and 230V,
or have a universal power supply.
Fuse Rating
The product is supplied with a single fuse in the live conducting path of the
mains power input. For reasons of safety it is important that the correct
rating and type of fuse is used. Incorrectly rated fuses could present a
possible fire hazard, under equipment fault conditions. The active fuse is
fitted on the outside rear panel of the unit.
Power Cable & Connection
An IEC power connector is supplied with the product which has a moulded
plug attached.
The mains plug or IEC power connector is used as the disconnect device.
The mains plug and IEC power connector shall remain readily operable to
disconnect the apparatus in case of a fault or emergency.
The mains lead is automatically configured for the country that the product
is being sent to, from one of:

iv
Safety & Installation
Atmosphere/Environment
This apparatus should be installed in an area that is not subject to excessive
temperature variation (<0°C, >50°C), moisture, dust or vibration.
This apparatus shall not be exposed to dripping or splashing, and no objects
filled with water, such as vases shall be placed on the apparatus.
Territory Voltage IEC Lead Type Image
UK & Middle East 230V UK 3 pin to IEC lead
Europe 230V European Schuko round 2 pin to
IEC lead
USA, Canada and
South America 115V 3 flat pin to IEC lead
Australia & New
Zealand 230V Australasian 3 flat pin to IEC lead
Connect the equipment in accordance with the connection details and
before applying power to the unit, check that the machine has the correct
operating voltage for your mains power supply.
This apparatus is of a class I construction. It must be connected to a mains
socket outlet with a protective earthing connection.
Important note: If there is an earth/ground terminal on the rear panel of
the product then it must be connected to Earth.
WEEE Directive
The Waste Electrical and Electronic Equipment (WEEE)
Directive was agreed on 13 February 2003, along with the
related Directive 2002/95/EC on Restrictions of the use of
certain Hazardous Substances in electrical and electronic
equipment (RoHS). The Waste Electrical and Electronic Equipment Directive
(WEEE) aims to minimise the impacts of electrical and electronic equipment
on the environment during their life times and when they become waste.
All products manufactured by Sonifex Ltd have the WEEE directive label
placed on the case. Sonifex Ltd will be happy to give you information about
local organisations that can reprocess the product when it reaches its “end
of use”, or alternatively all products that have reached “end of use” can be
returned to Sonifex and will be reprocessed correctly free of charge.

1
What Is A Telephone Hybrid? 1
1 What Is A Telephone Hybrid?
Telephone hybrids, or telephone balance units (TBUs) provide the interface
between professional audio equipment and the telephone networks. They
provide protection for your equipment and the telephone lines, allowing
for varying line signals and line conditions. Automatically cancelling out the
unwanted signal they also facilitate two-way communication down a single
telephone line.
A typical telephone hybrid has a telephone line connection, a handset
connection and separate terminals for audio input and output from a
broadcast mixer, or other professional audio source. This GSM unit has
no telephone line or handset connection, using an internal GSM receiver/
transmitter to receive and make calls.
A large proportion of Sonifex hybrids are used in radio and television
broadcasting applications for allowing external callers to be connected
to the studio mixing console. Most of the other units are supplied to
communication operations for allowing extremely effective conversion
between 4-wire audio circuits and standard telephone lines.
DHY-04G Single Automatic GSM Hybrid, AES/EBU
& Analogue I/O With Ethernet
A new addition to the DHY-04 range is the ability for the DHY-04G version to
be used on a GSM cellular (mobile) phone network instead of a telephone
(POTS) line. The DHY-04G can accept a SIM card in the rear panel slot and
by connecting a suitable GSM antenna, the DHY-04G can receive and make
high quality broadcast calls over the cellular network, converting the GSM
call to the 4 wire audio signal to and from a connected mixing console. The
GSM module used in the DHY-04G is quad-band GSM, so it can take and
make calls on any 2G GSM network.
Ideal for studios in remote locations, for OB vans and trucks on the
move, and in emergency situations where a telephone landline can’t be
guaranteed, the DHY-04G offers outstanding performance.
The DHY-04G has all features of the DHY-04 together with some additional
front panel indicators. There are two LEDs, one for SIM enabled and one for
GSM Network availability. Additionally there is a push button which allows
the GSM signal level to be displayed on the meter LEDs.
Product Function:
Provides separation between send and receive signals on a 2G GSM
network, provides professional level balanced input & output signals and
has echo cancellation.
Typical Applications:
Radio & TV station outside broadcast vehicles for talk shows, telephony
interface to the mixer. Backup hybrid to cover failure of main landline.

2
1 What Is A Telephone Hybrid?
Figure 1-1: DHY-04G Front & Rear
DHY-04G Single Freestanding Automatic GSM Hybrid
Features:
• Quad-Band EGSM 850 / 900 / 1800 /1900MHz.
• Rear panel 2G/GSM SIM card insertion.
• Ethernet web server control and configuration.
• Front panel speed dial buttons with redial.
• Signal strength LED display.
• LEDs for SIM enabled and GSM network availability.
• Automatic operation.
• Combined AES/EBU and analogue input and output.

3
What Is A Telephone Hybrid? 1
DHY-04GS Single Rackmount Automatic GSM Hybrid
Figure 1-2: DHY-04GS Front & Rear
DHY-04GT Twin Rackmount Automatic Digital TBU
Figure 1-3: DHY-04GT Front & Rear

4
1 What Is A Telephone Hybrid?
DHY-04HD Single Automatic HD Voice Hybrid, AES/
EBU & Analogue I/O With Ethernet
The DHY-04HD version can be used on a 3G or GSM cellular (mobile) phone
network instead of a telephone (POTS) line. The DHY-04HD can accept a
SIM card in the rear panel slot and by connecting a suitable GSM antenna,
the DHY-04HD can receive and make high quality broadcast calls over the
cellular network, converting the 3G or GSM call to the 4 wire audio signal to
and from a connected mixing console. The module used in the DHY-04HD is
quad-band GSM and 5 band UMTS/HSPA+, so it can take and make calls on
any 2G GSM, or 3G network.
Ideal for studios in remote locations, for OB vans and trucks on the
move, and in emergency situations where a telephone landline can’t be
guaranteed, the DHY-04HD offers outstanding performance.
The DHY-04HD has all features of the DHY-04 together with some additional
front panel indicators. There are two LEDs, one for SIM enabled and one for
GSM Network availability. Additionally there is a push button which allows
the mobile signal level to be displayed on the meter LEDs.
Product Function:
Provides separation between send and receive signals on a 2G or 3G
network, provides professional level balanced input & output signals and
has echo cancellation.
Typical Applications:
Radio & TV station outside broadcast vehicles for talk shows, telephony
interface to the mixer.
Backup hybrid to cover failure of main landline.
Main studio Hybrid for installations where the landline is unavailable or
unreliable
HD Voice:
HD Voice uses a coding system (also known as WB-AMR) for audio data that
provides a significant enhancement on the quality of cellular phone calls.
The use of HD Voice is dependent on 3 criteria -firstly the method has to be
supported by the network (and this may be limited by the users contract)
and when different networks are involved in the call the interoperability
between the networks. Secondly the actual equipment used by both ends
of the call must be HD Voice compatible. Both these requirements will be
established on call connection, which leads to the third criteria which is the
signal quality, and this can vary during the call. Normally the Hybrid will be
used in a fixed location install – even OB trucks are normally stationery - so
the position of the antenna can be refined for best signal quality, however
the far end maybe from a cellular phone so may vary in quality which can
lead to the familiar dynamic changes during a call. It is mostly true that
network providers will only handle HD Voice on 3G networks though, in
theory, it should be compatible with enhanced 2G networks.
This Manual:
The firmware used on the DHY-04HD is identical to the DHY-04G, so
throughout this manual rather than in each case referring to the
‘DHY-04G and the DHY-04HD’ we use just ‘DHY-04G/HD’ and the text,
figure, or screenshot will also refer to the DHY-04HD as well. There is only
one specific difference on the Home & Dialler pages from the webserver
where the call state will indicate a normal or an HD Voice call.
There is a separate technical spec and approvals info for the cellular
connection for the DHY-04HD.

5
What Is A Telephone Hybrid? 1
Figure 1-4: DHY-04HD Front & Rear
DHY-04HD Single Freestanding Automatic HD Voice Hybrid
Features:
• Five Band UMTS/HSPA+850 / 900 / 1800 / 1900 / 2100MHz.
• Rear Panel 2G GSM or 3G SIM card insertion.
• Ethernet web server control and configuration.
• Front panel speed dial buttons with redial.
• Signal strength LED display.
• LEDs for SIM enabled and GSM network availability.
• Automatic operation.
• Combined AES/EBU and analogue input and output.

2 Configuration & Controls - DHY-04G, DHY-04HD
6
Figure 2-1: Front Panel Controls
Line Hold/Connect
Button
Speed Dial
Buttons
AES Lock
LED
Gain Switches
Level Adjustment
LED Bargraphs & Signal
Strength Indicator
Signal Strength
Button
2 Configuration & Controls - DHY-04G, DHY-04HD
to redial the last number. The numbers are configured using the embedded
webserver.
AES/EBU Lock LED
This is a red/green LED with green indicating a successful lock to the
incoming AES/EBU signal, i.e. a valid AES signal is present. The LED is red for
a non-valid AES/EBU input.
Line Hold/Connect Button
This is the front panel button used to connect calls to, and disconnect calls
from, the telephone line. The line connect button flashes when an incoming
call is detected and illuminates to indicate the call has been connected.
Operation of this button can be remotely controlled by GPI.
Gain Switches (Level To & From The Line)
These switches allow gain/attenuation to be applied to the incoming &
outgoing analogue audio. Each switch has 3 positions. Rotating the switches
clockwise give gains of -6dB, 0dB & +6dB. The normal position for both the
Power
LED Indicator
Reset Button SIM Enabled LEDNetwork LED
Front Panel Controls
Power LED Indicator
The power LED indicates that the equipment is powered and operational
when illuminated.
Reset Button
In the unlikely event that the DHY-04G/HD unit fails to respond, press the
reset button to reboot the unit.
In extremis (especially valuable when the network settings have been
incorrectly entered) the unit can clear the settings to factory default by
pressing the reset three times in succession as follows – press reset; wait
for 7 seconds; press reset again; wait for 7 seconds; press reset again and
the unit will clear all the current settings and return to the factory defaults.
Speed Dial Buttons
Press the appropriate button to call Speed Dial settings 1-4. Press and hold
buttons 1-3 to call Speed Dial numbers 5-7 or press and hold Speed Dial 4

7
Configuration & Controls - DHY-04G, DHY-04HD 2
Figure 2-2: Internal Position of Jumper J1
transmit gain to the telephone line (lower switch) and for the receive gain
from telephone line (upper switch) is 0dB.
LED Bargraphs & Signal Strength Indicator
These 8 position bargraphs, by default, indicate the signal levels of the
incoming XLR audio signal from the mixer (lower) and outgoing XLR audio
to the mixer (upper). For best operation set the signal gain switches to
achieve all 3 yellow LEDs mostly illuminated with occasional audio peaks
lighting the first red LED.
The scale indicates from left to right: Green (-30dB, -18dB, -6dB); Yellow
(-3dB, 0dB, +3dB); & Red (+6dB, +9db). They also show the GSM signal
strength when the Signal Strenth Button is pressed.
Network LED
This blue LED indicates that the unit has established a connection with a
GSM base station.
SIM Enabled LED
This green LED indicates that the unit has a valid SIM card installed and that
it has been registered with the GSM network.
Signal Strength Button
Press and hold this button to use the bargraph display to indicate the GSM
signal strength from 0-100%.
Status & Operating Mode Information
The LED display is also used to indicate special operating modes and other
settings as follows:
Alternating 2 LEDs on, 2 LEDs off pattern indicates that the DHY-04G/HD is
checking the status of the Line Connect Button to test the Bootstrap Mode
(see page 29)
Alternating 4 LEDs on, 4 LEDs off pattern indicates that the DHY-04G/HD has
entered Bootstrap mode, because either the Line Hold/Connect Button was
held down for approximately 8 seconds at power up, or the main code has
been corrupted (most likely due to a previous incomplete firmware update).
Alternating 8 LEDs on, 8 LEDs off pattern indicates that the DHY-04G/HD
has received an update command from the web page and is updating the
firmware (valid in either Bootstrap or Normal operation).
DHY-04G/HD Internal Controls & Adjustments
If you need to get inside the unit to make configuration adjustments, simply
remove the 4 screws in the corners of the rear panel. The rear panel and
main PCB will slide backwards out of the metal chassis.
When re-inserting the main PCB, ensure that the PCB edges are in the
runners inside the chassis and also that the power LED and line connect
button are in the correct place in the front panel.
Warning: The power must be switched off at the supply or the power lead
must be disconnected before attempting to open the unit. Removal of the
cover can expose dangerous voltages.
Warning: The telephone line plug should be disconnected from the
telecommunications network exchange line before removing the cover.
Jumper and Select Switcher Functions
Put a 2 pin jumper over J1 to switch in an extra 10dB of audio input gain to
allow for use of domestic level mixing desks.

2 Configuration & Controls - DHY-04G, DHY-04HD
8
Pin2
Phase Signal
Pin 1
Screen Signal
Pin 3
Non-Phase Signal
Pin2
Phase Signal
Pin 1
Screen Signal
Pin 3
Non-Phase Signal
Rear Panel Controls & Connections
AES/EBU & Analogue Combined Line Output
The line output is an XLR 3 pin male connector with the following
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balanced analogue or AES/EBU audio by following the input, i.e. a
digital input produces a digital output.
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-Phase
Mic/Line & AES/EBU Input
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balanced floating). It is autosensing for either analogue balanced or
AES/EBU (left channel) signals.
Pin 1: Screen
Pin 2: Phase
Pin 3: Non-Phase
Mic/Line Input Select Switch
This push-button switch sets the input signal mode:
Switch depressed (in) - Mic input mode selected
Switch not depressed (out) - Line input mode selected
Adjusting the Microphone Gain Level
The Mic Level preset potentiometer controls the level of the input
signal when the Mic/Line Input Select Switch is set to Mic input. The
input signal level in Line mode is factory set and is not affected by this
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is balanced/floating with a maximum gain of 70dB. Use a jeweller’s
screwdriver to adjust the gain between 65dB and 35dB. The gain
range can be extended by ±6dB by using the front panel ‘Level to The
Line’ switch.
Remotes
The remote port allows you to control the line hold circuit from a mixing
desk or other remote device and also outputs opto-isolated outputs to
indicate the line hold status and the DTMF detect function.
The remote connector is a 9-way female (socket) ‘D’ type. To remotely
control the line connect, connect pin 1 to pin 2. The action of this remote
can act as momentary or latching by pin 6 having no connection or
connecting to 0V respectively.
Pins 3 & 7 are an opto-isolated remote line connect indicator and pins 5 & 7
are an opto-isolated DTMF detect output. They can use the local supply pins
4 & 8 to drive an LED indicator or a low current load.
Pin 1: Remote Line Connect Switch
Pin 2: Common – 0V
Pin 3: Opto-Isolated Line Connect Indicator - NPN Emitter
Pin 4: Common – 0V
Pin 5: Opto-Isolated User GPO (DTMF Detect*) Indicator - NPN Emitter
Pin 6: User GPI (Momentary/Latch Line Connect Switch - connect to
0V for latching action*)
Pin 7: Opto-Isolated Line Connect Indicator - NPN Collector
Pin 8: 5V out (current limited supply for pins 7 & 9)
Pin 9: Opto-Isolated User GPO Indicator - NPN Collector
The remote line connect indicator mimics the front panel Line Hold/
Connect Switch lamp, i.e. it flashes when ringing and is on when the line is
held.
*These GPO and GPI default functions are set to the same as the fixed GPIO
functions of the DHY-03.
Conference Audio/Record Output
This is an RJ45 analogue audio connector to cross connect to another DHY-
04G/HD. This will allow a single TBU channel on a mixing desk to handle 2
calls, one to each DHY-04G/HD. Alternatively the conference output signals

9
Configuration & Controls - DHY-04G, DHY-04HD 2
Mic Level Mic/Line Input
Select Switch
Configuration
Settings Switches
Figure 2-3: Rear Panel Controls
AES/EBU & Analogue
Output
Mic/Line/AES/EBU
Input
Conference
Audio
Remotes
Connector
GSM
Antenna
SIM
Card
Serial RS232
Port
Ethernet
Port
Mains IEC
Inlet
Earth Bond
Point
can be used as a record output by using the webserver interface. The
output is then a sum of the caller and main audio input so both sides of the
conversation can be recorded from this output.
Pin 1: N/C
Pin 2: N/C
Pin 3: Conference Input (phase)
Pin 4: Conference or Record Output (phase)
Pin 5: Conference or Record Output (non-phase)
Pin 6: Conference Input (non-phase)
Pin 7: N/C
Pin 8: N/C
GSM Antenna
This is an SMA bulkhead connection to connect to an antenna to
communicate with the GSM base station. We provide a simple ‘stubby’
antenna that is suitable for most applications, but where the signal is poor
or the install is in a sensitive area, you should use hi gain antennas and/or
low loss extension cables.
SIM Card Slot
This is a standard SIM card slot (also known as mini SIM or 2FF).
RS232 Serial Port
The serial port allows direct connection to a 9 way ‘D’ type connector on a
PC via a pin to pin cable. See chapter 5 for details about this interface.
Pin 1: N/C Pin 6: N/C
Pin 2: TxD Pin 7: CTS
Pin 3: RxD Pin 8: RTS
Pin 4: N/C Pin 9: N/C
Pin 5: Ground
Ethernet Port
This is an RJ45 port which should be connected via CAT5 cable to an
Ethernet device or switch. The port will automatically set the pins to suit
(Auto-MDX) and select the maximum available speed (10Mbps or 100Mbps)
depending on the connected infrastructure (Auto-Negotiation).

2 Configuration & Controls - DHY-04G, DHY-04HD
10
Unused
Noise Gate Select
Force Static
IP Address
1 2 3 4 5 6 7 8
ON
OFF
Network
Cancellation Enable
Auto Answer Enable
Unused
Ducking Enable
Unused
Figure 2-4: Configuration Settings Switches
Mains Input
The power supply is connected via a filtered IEC Plug and is continuously
rated 85-264V AC @ 47-63Hz.
Protective Earth Terminal
This earth bond screw terminal is a screen terminal that must be connected
to an earth point.
Configuration Settings DIPSwitches
The SETTINGS switches are used to configure the DHY-04G/HD in the modes
that you want it to operate. A label on the top panel of the unit shows the
orientation of the switches:
The following paragraphs describe the function of each switch; the default
or normal position is shown in curly brackets.
Noise Gate Select - SW1 {ON}
An output noise gate operates when the telephone signal is below the noise
gate threshold control. This noise gate reduces the output gain by 34dB
during low level signal conditions. This eliminates the effects of telephone
line cross talk. The noise gate can be switched off if you don’t wish to use it
by switching SW1 to the OFF position.
Ducking Enable - SW2 {ON}
This switch allows the received signal to be automatically attenuated by
18db when both received and sent audio are present in the hybrid. This
allows an operator in the studio to talk over the caller at all times.
Ring Detector (Auto Answer) Enable - SW4 {ON}
This switch enables the integrated ring detector, which automatically
answers incoming calls after the number of rings set using the webserver
(Configuration - Telephone). The default is 2 rings.
Note double cadence ring tones count both rings in the cadence pattern.
Force Static IP Address – SW6 {OFF}
When SW6 is enabled (ON) during the unit power-up routines, the Network
settings are overridden to force the unit to use a static IP address of
192.168.0.100 with a subnet mask of 255.255.255.0
Network Cancellation Enable – SW7 {OFF}
When switch SW7 is enabled (ON) the DHY-04G/HD performs the echo
cancellation routine on the incoming signal from the telephone line. This is
not normally required by a GSM network as the signal is already cancelled
in the GSM network, but it may be enabled for special circumstances.