DH30 D T H IGITAL
DH30 DIGITAL TELEPHONE HYBRID
DH30 Product Manual
TABLE OF CONTENTS
SECTION
1 ........ INTRODUCTION ........................................................................................ 4
...................... WHAT IS A HYBRID? .................................................................... 4
...................... DH30 FEATURES ........................................................................ 5
...................... WHAT COMES WITH THE DH30? .................................................... 6
...................... PRODUCT REGISTRATION AND TECHNICAL SUPPORT .............................. 7
...................... OPERATIONAL REQUIREMENTS ......................................................... 7
SECTION
2 ........ CONNECTING THE EQUIPMENT ..................................................................... 8
...................... TYPICAL DH30 DIGITAL INSTALLATION ............................................. 8
...................... CONSOLE CONNECTIONS — DIGITAL AUDIO ....................................... 8
...................... TYPICAL DH30 ANALOG INSTALLATION ............................................. 9
...................... CONSOLE CONNECTIONS — ANALOG AUDIO ....................................... 9
...................... ADDITIONAL CONNECTIONS ............................................................ 10
SECTION
3 ........ SETUP AND OPERATION ............................................................................. 12
...................... FRONT PANEL CONTROLS ............................................................... 12
...................... HANDLING CALLS ........................................................................ 14
...................... RECORDING CALLS ....................................................................... 15
...................... USING THE NAVIGATING BUTTONS AND ADJUSTING PARAMETERS .............. 16
...................... VIEWING OF CHANGING SETTINGS THROUGH THE LCD PANEL ................ 17
...................... USING PRESETS ........................................................................... 18
...................... SETTING LEVELS .......................................................................... 18
SECTION
4 ........ AUTO MIX-MINUS AND ACOUSTIC ECHO CANCELLATION .................................... 19
...................... MIX-MINUS/ACOUSTIC ECHO CANCELLATION ...................................... 19
...................... ECHO REDUCTION ....................................................................... 20
...................... EC TRAIN ................................................................................. 20
...................... DIAGNOSTICS .............................................................................. 21
...................... TEST SIGNAL .............................................................................. 21
SECTION
5 ........ CUSTOMIZING YOUR SYSTEM ....................................................................... 22
...................... SETTING CALLER PROCESSING ......................................................... 22
...................... SYSTEM PARAMETERS .................................................................... 25
SECTION
6 ........ SPECIFICATIONS ....................................................................................... 28
...................... DIMENSIONS ............................................................................... 28
...................... WEIGHT .................................................................................... 28
...................... OPERATING TEMPERATURE ............................................................. 28
...................... FRONT PANEL CONTROLS ............................................................... 28
...................... REAR PANEL CONNECTORS ............................................................. 28
...................... TELEPHONE TRANSMIT .................................................................. 29
...................... TELEPHONE RECEIVE .................................................................... 30
...................... ECHO CANCELLATION/MIX-MINUS .................................................... 30
...................... TELCO CANCELLATION ................................................................... 30
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Comrex Corporation
TABLE OF CONTENTS (CONT.)
2
SECTION
7 ........ PINOUTS ............................................................................................... 31
...................... REMOTE CONNECTOR ................................................................... 31
...................... RS232 CONNECTOR .................................................................... 31
...................... RECORD CONTROL ....................................................................... 32
...................... LINE CONNECTOR ........................................................................ 32
...................... SET CONNECTOR ......................................................................... 32
...................... XLR CONNECTOR ........................................................................ 32
SECTION
8 ........ SERIAL COMMUNICATIONS PROTOCOL ............................................................ 33
SECTION
9 ........ DH30 AUDIO FLOW ............................................................................... 35
SECTION
10 ...... COMPLIANCE .......................................................................................... 36
...................... FCC PART 15 COMPLIANCE .......................................................... 36
...................... FCC PART 68 COMPLIANCE .......................................................... 36
...................... IC COMPLIANCE .......................................................................... 37
...................... INTERNATIONAL COMPLIANCE .......................................................... 38
SECTION
11 ...... USER-DEFINED PRESETS WORKSHEET ........................................................... 39
SECTION
12 ...... GLOSSARY .............................................................................................. 41
DH30 Product Manual
About Comrex
Comrex has been building reliable, high quality broadcast equipment since 1961.
Our products are used daily in every part of the world by networks, stations and
program producers.
Every product we manufacture has been carefully designed to function flawlessly,
under the harshest conditions, over many years of use. Each unit we ship has
been individually and thoroughly tested. Most items are available off-the-shelf,
either directly from Comrex or from our stocking dealers.
Comrex stands behind its products. We promise that if you call us for technical
assistance, you will talk directly with someone who knows about the equipment
and will do everything possible to help you.
Our toll free number in North America is 800-237-1776. Product information
along with engineering notes and user reports are available on our website at
http://www.comrex.com. Our E-Mail address is [email protected]
Warranty and Disclaimer
All equipment manufactured by Comrex Corporation is warranted by Comrex
against defects in material and workmanship for one year from the date of
original purchase, as verified by the return of the Warranty Registration Card.
During the warranty period, we will repair or, at our option, replace at no charge
a product that proves to be defective, provided you obtain return authorization
from Comrex and return the product, shipping prepaid, to Comrex Corporation,
19 Pine Road, Devens, MA 01432 USA. For return authorization, contact Comrex
at 978-784-1776 or fax 978-784-1717.
This Warranty does not apply if the product has been damaged by accident or
misuse or as the result of service or modification performed by anyone other than
Comrex Corporation.
With the exception of the warranties set forth above, Comrex Corporation makes
no other warranties, expressed or implied or statutory, including but not limited
to warranties of merchantability and fitness for a particular purpose, which are
hereby expressly disclaimed. In no event shall Comrex Corporation have any
liability for indirect, consequential or punitive damages resulting from the use of
this product.
Copyright Notice
The Comrex proprietary code and licensed, third party proprietary code residing
in and otherwise associated with this product are protected by copyright law and
international treaties. Unauthorized reproduction or distribution of this product,
or any portion of it, may result in civil and criminal sanctions, and will be
prosecuted to the fullest extent of the law.
US Government Restricted Rights - Use, duplication, or disclosure by the US
Government is subject to restrictions set forth in subparagraph (c)(1)(ii) of the
Rights in Technical Data and Computer Software clause at DFARS (48 CFR)
252.227-7013 or subparagraphs (c)(1) and (2) of the Commercial Computer
Software-Restricted Rights clause at FAR (48 CFR) 52.227-19, as applicable.
3
Comrex Corporation
SECTION 1.
WHAT IS A HYBRID?
INTRODUCTION
Simply put, a hybrid is a device that separates send and receive audio on a
phone line. While the public switched telephone network utilizes separate
channels for audio in each direction of a phone call, these two signals are
mixed together before being sent to the end user. This way, only one pair of
wires is required from your telephone to the telco central office. To use
telephone company terms, the telephone network is a “4 wire” system,
while the local loop is a “2 wire” system.
When recording or airing telephone conversations in a studio environment,
it’s important that telephone audio be “4 wire.” This is because the audio
program usually already contains the audio of the “studio host.” If the
telephone audio also contains some of the “studio host,” these two signals
will be added together by the mixing console. The effect will be distortion
in the voice of the “studio host.” In essence, a hybrid converts the “2 wire”
telephone line back into a “4 wire” audio path.
It seems counter-intuitive, but the main goal of a studio hybrid is to make
the people in the studio sound better. If the hybrid isn’t working well,
people speaking from the studio will sound “hollow” or like they’re “talking
into a barrel.” This is due to the strange effect of mixing microphone audio
with telephone “bleed-through.” Of course, our hybrids also improve the
audio of callers, filtering out hum and noise as well as adjusting levels
between loud and soft speakers.
It’s our opinion that with the advent of cheap telephones, cordless phones
and cellphones, telephone audio has gotten decidedly worse in recent
years. While a hybrid can cleanup noise to some extent, it can’t remove
distortion caused by the far end telephone. If you find some calls sound
good on air and some don’t, it’s probably due to the large disparity in audio
quality of today’s telephone sets.
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DH30 Product Manual
DH30 FEATURES
The DH30 provides a high quality telephone interface between a
telephone line and audio equipment to help bring uniformity and high
quality sound to a broadcast talk show environment. This telephone
interconnection system uses digital hybrid technology to continually adapt
to telephone-line conditions , providing consistent high-quality sound.
Here is a list of the DH30 Digital Telephone Hybrid’s features:
v
Selectable auto mix-minus and acoustic echo cancellation, allowing for
operation in a variety of closed or open studio environments.
v Continually adapts to telephone-line conditions, providing the best,
most-reliable null possible.
v Programmable auto-answer, auto-disconnect and caller control
functions.
v Call monitoring capability with a built-in 2-watt monitoring amplifier
and front-panel volume control.
v AES/EBU connections allow for a direct digital audio link
between the DH30 and a digital console.
v Analog connections are made using the send and cue inputs and the
caller and aux outputs.
v Each input and output has its own adjustable gain control, ensuring
the best audio mix in every application.
v The DH30’s 24-bit digital signal processing (DSP) produces high-
quality audio with expansion, compression, equalization and bass
boost capabilities. The downward expander, compressor and 3-band
EQ allow you to fine tune the sound of the caller audio.
v The telephone echo cancellation provides a high quality telephone
interface between a standard analog telephone line and user audio
equipment. The primary function of the hybrid is to separate send and
caller audio (null). The hybrid provides >55 dB send/caller isolation
between 250 Hz to 3.5 kHz.
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Comrex Corporation
v The DH30 is easily customized. The Enter, Esc, Volume control
buttons, and the LCD display provide useful control options, including
integrated monitor amplifier with push-button volume control,
adjustable caller audio control, adjustable three-band equalization,
password protection and adjustable compressor/limiter and expander.
v The DH30 presets are the programmable operating parameters that
control how the DH30 responds to the telephone line. The DH30 can
store up to three presets. The unit ships with Preset 1 containing a set
of default values. You can keep these settings or modify them, and
you can also set up two additional presets. The Presets feature allows
you to easily change to a completely different operating profile. If
power is lost, the DH30 powers up with the last preset used, so custom
presets are not lost.
Caller
Off
On
Cu
e
Re
c
-36
-24
-12
-3
-4
0
+4
+8
Send
DH30
(Domestic or International)
Specialists
in Remote
Broadcast
Audio
Transmission
7-foot Modular Telephone Cable
6
DH30
Digital Telephone Hybrid
Product Manual
DH30 Installation and Operations Manual 30
Esc
-36
-24
-12
-3
-4
0
+4
+8
Volume
Enter
DH
WHAT COMES WITH THE
DH30?
DH30 Product Manual
PRODUCT REGISTRATION AND
TECHNICAL SUPPORT
Please register your DH30 by filling out and returning the enclosed
warranty registration card or by visiting our website www.comrex.com/
warranty.html. When your DH30 is properly registered, Comrex can better
serve you should you require technical assistance or need upgrades or new
product information.
If you have any problems or simply need a question answered, please call
us at 978-784-1776. Our toll free number in North America is 800-237-1776.
Product information along with engineering notes and user reports are
available on our website at http://www.comrex.com. Our email address is
[email protected]
OPERATIONAL REQUIREMENTS
The DH30 is designed to work in almost any acoustic environment.
However, to improve audio quality and ease installation, we recommend
that you take the following factors into consideration:
Acoustic Room Treatment — Rooms that have large areas of windows,
white boards, hard floors, etc. are acoustically live. These areas increase the
amount of audio reverberation in the room which, in turn, reduces audio
quality. To achieve the best results using the DH30, you should minimize
the amount of audio reverberation wherever possible. You can improve
room acoustics by installing acoustic panels, drapes and other wall fabrics.
Another way to improve overall room acoustics is to keep room noise (i.e.
computers and fans) to a minimum.
Environmental — The room temperature at which the DH30 can operate
ranges from 32–100 degrees F / 0–38 degrees C, with relative humidity of
0–80 percent.
Telephone Line — The DH30 operates on standard telephone lines and
connects to a standard RJ11C modular jack. If you do not have an RJ11C
jack where you want to install the DH30, call your telephone company for
installation.
Equipment Placement — The DH30 is designed for installation in a
standard 19-inch equipment rack.
Power — The DH30 automatically adjusts to voltages between 100–240
Vac, 50–60 Hz. Manual voltage switching is not required.
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Comrex Corporation
SECTION 2.
CONNECTING THE EQUIPMENT
All equipment connections are made through the back panel. Position the
DH30 so that the connectors are readily accessible and their pin orientation
is visible. To use the functions associated with these connections, refer to
“Setup and Operation,” beginning on page 12.
Telephone Line
Console Out
TYPICAL DH30 DIGITAL
INSTALLATION
Console In
VOLTAGE RANGE 100V - 240V 2A
FREQUENCY 50Hz / 60Hz
AES/EBU IN AES/EBU OUT
RS-232
RECORD CONTROL
REMOTE
Record
Control
CONSOLE CONNECTIONS —
DIGITAL AUDIO
Telephone Set
MONITOR
SEND IN
CUE IN
CALLER OUT
AUX OUT
TELCO
LINE SET
Record Input
AES/EBU In — This is the audio that the caller will hear. Connect an AES/
EBU output from the studio console to the AES/EBU IN input of the DH30.
This connection provides a digital audio input directly to the Digital Signal
Processor (DSP). The AES/EBU digital audio input is stereo. The left
channel is designated as the send audio input and the right channel is the
cue audio input. The DH30 automatically synchronizes to the AES/EBU
sample rate connected at the input.
AES/EBU Out — This is the output of the callers voice. Connect the AES/
EBU OUT to an AES/EBU input channel of the studio console.
This connection provides a digital audio output directly from the DSP. The
output sample rate follows the AES/EBU input sample rate. If no AES/EBU
sample rate is provided, the rate defaults to 32 kHz.
The AES/EBU digital audio output is stereo. The left channel is designated
as the caller audio out and the right channel contains the send or cue
audio (whichever is selected via the CUE button).
Note: You should cycle power anytime you disconnect AES/EBU
connectors from the DH30.
8
DH30 Product Manual
Telephone Line
TYPICAL DH30 ANALOG
INSTALLATION
Telephone Set
Console In
Console Out
VOLTAGE RANGE 100V - 240V 2A
FREQUENCY 50Hz / 60Hz
AES/EBU IN
AES/EBU OUT
RS-232
RECORD CONTROL
REMOTE
MONITOR
SEND IN
CUE IN
CALLER OUT
AUX OUT
TELCO
LINE SET
Record Input
Record Control
CONSOLE CONNECTIONS —
ANALOG AUDIO
Send In — This is the audio that the caller will hear. Connect a mic or line
output from the studio console to the SEND IN input of the DH30.
If the DH30’s echo canceller feature is disabled, you must send mix-minus
audio to the SEND IN connector. If you are using a microphone connected
directly to the DH30 that requires phantom power, you will need to
activate the phantom power circuit. Contact Comrex technical support.
Cue In — This is the audio the caller will hear when the cue feature,
located on the front panel, is activated. Connect a mic or line output from
the studio console to the CUE IN input of the DH30.
No auto mix-minus or acoustic echo cancellation is performed on the Cue
audio, and therefore, the audio sent to this input must be a mix-minus.
Caller Out — This is the output of the caller’s voice. Connect the CALLER
OUT to an input channel of the studio console.
Aux Out — This is the output of the caller audio and the send or cue
audio (whichever is selected via the CUE button). Connect the AUX OUT to
an input channel of your studio console or recording device.
The caller/send mix is programmable through the front panel LCD display.
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Comrex Corporation
ADDITIONAL CONNECTIONS
TELCO
LINE SET
Telephone Line Connections — The DH30 operates on one standard
POTS (plain old telephone service) analog telephone line or one analog
extension from a PBX via a standard RJ11C modular jack. Note: Some
telephone lines do not provide battery voltage (dry line, no DC offset
voltage). If your line does not, the DH30 may be configured by qualified
personnel for dry line operation. Please contact Comrex technical support
for details.
Line — Plug your telephone line into the RJ11C LINE jack.
Set — Plug your telephone set into the RJ11C SET jack.
REMOTE
MONITOR
Remote — Connect a DB25 parallel cable to this connector to provide
control and status via your console remote port or contact-closure
switches. This connector also contains unbalanced audio inputs and
outputs. See “Pinouts” on pages 31-32.
Monitor — Connect a speaker or mono headphones to this 1/4” phone
jack to produce a 2-watt amplified audio signal for call monitoring. Only
caller audio is present on this output. Stereo headphones will contain
caller audio in one earpiece only.
The front panel volume buttons control the level of this output. See the
“Setup and Operation” section on pages 12-13 for front panel usage.
RECORD CONTROL
Record Control — Control a tape deck or other external recording device
with this DB9 RECORD CONTROL connector.
This DB9 female connector sends start, stop and enable commands for
automatic telephone call recording. This connector provides control only.
Use the AUX OUT connector to route audio to the recording device.
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DH30 Product Manual
RS232
RS232 Serial Port — This DB9 female connector connects to the serial
port of a PC or other RS232 device. The serial port settings are fixed at
9600 baud, 8-bit, no parity, 1 stop bit. This port receives commands to
remotely control operation, request status or download firmware
upgrades. Refer to “Serial Communications Protocol” on pages 33-34.
VOLTAGE RANGE 100V - 240V 2A
FREQUENCY 50Hz / 60Hz
Power Connection — This connection automatically adjusts to accept
voltages between 100–240 Vac, 50/60 Hz.
The AC power cord is an IEC type connector, which allows use of
domestic US power cords as well as international power cords.
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Comrex Corporation
SECTION 3.
SETUP AND OPERATION
As soon as you connect power and the DH30 completes its initialization
cycle (about two seconds), it is functional. The factory default settings that
are active upon power-up can accommodate basic operation. You can
immediately use the hybrid to connect, disconnect and record calls.
Before initial use, it is recommended that the DH30 be calibrated to your
telephone system and audio controls. Depending on your site’s unique
needs, some settings may require modification.
FRONT PANEL CONTROLS
Caller
Of
f
On
Cu
e
Re
c
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
Send
30
Esc
DH
Volume
Enter
Off
On
On and Off — When the DH30 is plugged in, it defaults with the hybrid
off, indicated by the red OFF LED.
The ON button connects the DH30 to the telephone line and causes the
hybrid to adapt to the line. Pressing the ON button while the DH30 is
connected to a telephone line readapts the hybrid. A steady green LED
indicates that the DH30 is on. A flashing green LED indicates an
incoming call.
Re
c
When the OFF button is pressed, the DH30 disconnects from the
telephone line and mutes caller audio. The red OFF LED illuminates.
Record — The REC button controls the start or stop of an external
recording device connected to the DH30 through the RECORD CONTROL
output on the rear panel.
Cu
e
The RECORD LED flashes red when recording, appears solid red in recordready (standby) mode and is not lit when record mode is off.
Cue — The CUE button enables the talent to speak to a caller off the air.
When you press the CUE button, the CUE LED illuminates and audio from
the cue input is routed to the caller. When the CUE button is off, the CUE
LED turns off and audio from the send input is routed to the caller.
Neither auto mix-minus nor acoustic echo cancellation is performed on
the cue input. Therefore, a mix-minus audio source must be provided to
the cue input.
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DH30 Product Manual
VU Meters (Send and Caller) — These LED’s indicate the audio levels at
the SEND and CALLER XLR connectors.
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
Send
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
Caller
The SEND meter indicates the level of the audio sent to the caller. The input
gain should be set so that the average send level is at 0 dBU with occasional
peaks to +4 dBU.
The CALLER meter indicates the level of the audio being received by the
hybrid. Caller processing (compressor, EQ, gain and the other caller
processing parameters) is reflected in the CALLER meter reading.
Volume
Volume — The up and down arrows (p/q) raise or lower the volume
level of the internal 2-watt power amplifier to the speaker or headphone
connected to the MONITOR jack on the rear panel. Pressing a button once
increases or decreases the level by 3 dB. Holding a button sweeps the
volume up or down.
At power up, the monitor volume defaults to a nominal reference of
0dB. The volume may be adjusted between +18 dB and –27 dB. Reducing
the volume past –27 dB turns off the monitor and mutes the power
amplifier output, indicated by the solid red V OLUME LED.
Pressing p and qsimultaneously will reset the volume to nominal (0 dBu).
Enter
Esc
Enter, Esc, p/q — These four buttons allow you to navigate through the
menus and adjust parameters on the adjacent LCD panel. They are also
used in setting and entering the password.
LCD Display — This LCD display is a two-line, 16-character alphanumeric
display. The first line displays the main menu categories. The second line
displays the adjustable parameters.
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Comrex Corporation
HANDLING CALLS
Receiving a Call — To set up the DH30 for automatic answer or
disconnect, refer to “System Parameters” (pages 25–26).
vOn-Air — When a call rings on the telephone line connected to
the DH30, the ON LED will flash and the telephone connected to
the SET output will ring. Answer the call by pressing the ON button
or activating the hybrid from your remote console control (if
applicable). This routes the call through the hybrid, and the green
ON LED illuminates. Upon connection, the DH30 automatically
adjusts to line conditions.
vOff-Air — Answer the call by picking up the telephone handset
and talking to your party over the telephone. Do not press ON.
Disconnecting a Call — If the call is routed through the DH30 (the ON
LED is lit), press the OFF button to disconnect the call. The OFF LED
illuminates, and the ON LED goes out. Note: If the handset is off hook
when the Off button is pressed, the caller will remain on the handset.
If your call is through the handset only (the red OFF LED is lit), hang up
when the conversation is complete.
Making a Call — Call the party normally, using your telephone handset.
After the other party has answered, put the call on-air by pressing the ON
button. The ON LED lights and the DH30 takes control of the call,
disabling the telephone set. You may safely hang up the handset without
disconnecting your call. When the conversation is complete, press the OFF
button to disconnect the call. If you wish to take the caller off the air
without hanging up, pick up the handset and then press the OFF button.
To make a telephone call off-air, call the party normally, using your
telephone handset. After the other party has answered, conduct your call
as you normally would and hang up the handset when finished.
14
DH30 Product Manual
RECORDING CALLS
The record function controls a recording device through the DB9 RECORD
CONTROL connecter. To use the record function, a recording device must be
connected to the DB9 RECORD CONTROL connector. The AUX OUT connector
of the DH30 must also be connected to the recording device.
The record function has three settings: off, record-ready (standby) and on
(recording). Pressing the RECORD button has different effects, depending on
whether the DH30 is on or off.
When the hybrid is recording, the LED flashes. When the hybrid is in
record-ready mode, the LED is steady. And when the hybrid is not
recording, the LED is not lit.
Recording Manually — When the hybrid is on, press RECORD to begin
recording. The LED will flash. When you turn the hybrid off or when you
press RECORD again, recording will stop and the LED will go off.
Using Record Ready — Press RECORD when the hybrid is off. The RECORD
LED will illuminate. When the ON button is pressed, recording begins
automatically and the RECORD LED flashes. When the hybrid is turned off or
when you manually press the RECORD button again, recording stops and the
RECORD LED becomes steady, indicating record-ready mode is still active.
Note: The ON and OFF buttons of the hybrid control the start and stop
signals of the record connector in record-ready mode. This is ideal for
unsupervised applications that use auto answer/disconnect in
conjunction with recording devices.
15
Comrex Corporation
Caller
2 GAIN
SEND IN
USING THE NAVIGATING
BUTTONS AND ADJUSTING
PARAMETERS
Of
f
On
Cu
e
Re
c
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
-3
6
-2
4
-1
2
-3
-4
0
+4
+8
Send
30
Esc
DH
Volume
Enter
LCD Panel
To scroll through the menu items on the LCD panel, press the UP and
DOWN buttons. When a desired menu item is reached, press ENTER. Use the
UP and DOWN buttons to scroll through the parameters. Press ESC to go
back one level in the menu. At the end of the list of menu items, the menu
will wrap around to the beginning.
Adjusting Parameters — As you enter a menu item and reach an
adjustable parameter, the current value is displayed on the second line. To
adjust the parameter, press ENTER. The parameter will begin to blink,
indicating that the UP and DOWN buttons will adjust the value. As values are
adjusted up and down, the change takes effect immediately. For example,
as you adjust the caller out gain, you’ll hear the level change. While
adjusting a parameter up and down, an asterisk appears when the
displayed value matches the preset value.
When you have adjusted the parameter to the desired value, press ENTER.
This stores the value in the menu and it becomes the new preset value. If
you press ESC, no changes will be made to the parameter, leaving the
original setting as the preset value.
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DH30 Product Manual
VIEWING OR CHANGING
SETTINGS THROUGH THE
LCD PANEL
Menu Category
The table below summarizes the settings available through the LCD panel.
Refer to “User-Defined Presets Worksheet” (pages 39-40) for a worksheet
version of this chart.
Selections
Presets
Function
Defaults
Store 3 Sets of Unique Configurations that can be Selected
Select Preset
Selects Preset 1, 2, or 3 - loads all parameters associated with
1
selected preset
Copy Preset
Copies settings from the active preset into one of the other two
N/A
presets
Recall Default
Restores settings to factory default for current preset
Send In
Adjusts send audio level as heard by caller
Send Mic/Line
Adjusts send input for mic or line input
Line
Cue In
Adjusts cue audio level as heard by caller
0dB
Cue Mic/Line
Adjusts cue input for mic or line input
Line
Call Out Gain
Adjusts caller's audio level out of DH30
0dB
Aux Send
Adjusts send audio level at aux output
0dB
Aux Caller
Adjusts caller's audio level at aux output
0dB
3 Band EQ
Adjusts to tonal quality of the caller's voice
Bypass
Compressor
Enables DH30 to handle wide range of caller voice levels
Bypass
Expander
Attenuates line or background noise when caller is not talking
Bypass
Bass Boost
Enhances caller bass
Bypass
Caller Control
Allows talent to talk over caller
0dB
Noise Burst
Toggles whether or not a noise burst is sent down telephone line
On
Gain
N/A
Set Gain for Inputs and Outputs
Caller Processing
0dB
Adjust Audio for Incoming Calls
when connection to the phone line is made
Echo Canceller
Adjust Auto Mix-Minus/AEC
Mix-minus/AEC
Turns mix-minus/acoustic echo cancellation on/off
Echo Reduction
Selects echo reduction enhancement
On
Normal
EC Train
Trains echo canceller to the room environment (acoustic) or
N/A
Diagnostics
Displays measurements for troubleshooting
N/A
Test Signal
Turns on/off noise generator to test receive or transmit
Off
Auto Answer
Turns on/off automatic phone answer on first ring
Auto Disconnect
Selects type of auto disconnect
Off
Remote Control
Sets remote on pin for momentary or latching control
Momentary
Remote Auxpins
Selects aux pins for preset selection or audio muting control
Sample Rate
Displays system sample rate
studio (auto mix-minus) during setup
System
Adjusts Various System Parameters
Off
Select
Presets
32,000
internal
Send to Aux
Selects type of send audio routed to aux output
Set Passcode
Sets passcode used to lock and unlock adjustment presets
ppqq
Processed
Version
Displays firmware version of DH30
N/A
On/Off
Toggles adjustment of presets off and on, offering protection to
Enter
Lock Panel
Locks Adjustment of Parameters
Off
preset parameters. "L" appears in the bottom right corner of LED
screen when locked
17
Comrex Corporation
USING PRESETS
Preset 1
Preset 2
Preset 3
The DH30 allows the pre-configuration of up to three complete usage
profiles through the Presets menu.
First, select the preset (Preset 1, Preset 2, or Preset 3) you want to work
with.
Within the Preset menu you can copy preset values into one of the other
two presets, you can edit current parameters or you can choose to restore
the values in that preset to the factory defaults (Recall Defaults option).
Any time you change values within the LCD menus, you are changing the
values of the selected preset. Once you have entered changes in a preset,
those values remain until they are manually reconfigured. Losing power
does not affect the presets.
SETTING LEVELS
When adjusting levels, the hybrid should be connected to the telephone
line. Have someone call the DH30 from another location. Answer the line
by pressing the ON button. (If the auto-answer feature is active, the unit
will answer the call after one complete ring.) Modify the level settings as
follows:
1. Select Gain from the LCD panel, and use the ARROW keys to locate
the appropriate function.
2. Press ENTER.
3. Use the ARROW buttons to adjust levels. (You can observe SEND IN
and CALLER OUT level changes on the SEND and CALLER meter LED’s.)
4. Press ENTER to save the value into the current-selected preset.
Submenu Options
Send In Gain
Function
The Send In level is set for a nominal input level of 0dB.
This line-level input is adjustable from -20dB to 20dB
Send Mic/Line Gain
Adds 55 dB fixed gain
Hints for Setting
Adjust to select a value that registers
0dB on the Send meter LED
Set to LINE unless you are connecting
directly to a microphone
Cue In Gain
The Cue In level is set for a nominal input level of 0dB.
With Cue audio selected, adjust to
This input level is adjustable from -20dB to 20dB
select a value that registers 0dB on
the Send meter LED
Cue Mic/Line Gain
Adds 55 dB fixed gain
Set to LINE unless you are connecting
directly to a microphone
Caller Out Gain
The Caller Out level is set for a nominal output value of 0dB.
Adjust to match the nominal input
This output is adjustable from -20dB to 20dB
level requirements of your console
Aux Send/Caller
The Aux Send and Caller level is set for a nominal output
Adjust the balance of this and the
Output Gain
value of 0dB. This output is adjustable from -20dB to 20dB
previous option so they are matched
in level for nominal input to your
18
recorder from the AUX output
DH30 Product Manual
SECTION 4.
MIX-MINUS/ACOUSTIC ECHO
CANCELLATION
AUTO MIX-MINUS AND ACOUSTIC ECHO CANCELLATION
The DH30 can cancel two types of echo — electronic and acoustic (room)
echo. By setting the mix-minus/acoustic echo cancellation, you can cancel
either or both types of echo.
Electronic Echo — is the echo caused by the caller’s audio being sent
back to the caller through the mixing console. This can be prevented by
creating a mix-minus at the mixing console. Mix-minus is the mix of all
studio audio sources except caller audio.
The Automatic mix-minus feature in this hybrid can be effective in
removing the caller from the outgoing audio feed (the feed being sent back
down the phone line). It does have its limitations, however. Because this
mix-minus generation works on the same principles as the send-receive
separation, changes in program level (e.g. riding a fader on the console)
will cause the mix-minus feed to adapt, causing performance issues and
audio distortion. The mix- minus generator is also very sensitive to nonlinear processing (mic processors or compressor-limiters), so these must be
left out of the signal chain. For the same reason, the mix-minus generation
will cause severe distortion on overdriven audio levels.
In practice, whenever practical, we recommend creation of a true mixminus feed in the studio rather than engaging this function. We consider
this feature useful as a last resort, when no true mix-minus is technically
possible.
Acoustic Echo — is the echo in a room environment. In an application
such as a talk show, speaker audio may be picked up by microphones and
fed back to the caller. Acoustic echo cancellation prevents this audio from
being fed back to the caller.
Mix-minus and acoustic echo cancellation (AEC) are turned on and off
through the Echo Canceller menu in the LCD panel. Although the DSP
automatically adjusts to cancel echo, it is recommended you train the echo
canceller to the echo when you first install the DH30. See “EC Train” on
page 20.
1.
2.
3.
4.
Use the ARROW buttons to display Echo Canceller. Press ENTER.
Use ARROW buttons to display Mix-Minus/AEC.
Select On or Off, then press ENTER to activate your selection.
Press ESC to return to the previous menu level.
Note: If your mixing console is feeding mix-minus to the DH30 and you
have removed acoustic echo in the studio, you should turn off the MixMinus/AEC function of the DH30.
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Comrex Corporation
ECHO REDUCTION
Echo reduction provides additional echo cancelling capability to the echo
canceller in difficult acoustical environments. To activate, set the amount
of non-linear processing the DH30 uses. The more aggressive the setting,
the greater the chance of cutting off the caller’s audio.
1. Use the ARROW buttons to display Echo Canceller. Press ENTER.
2. Use the ARROW buttons to display Echo Reduction. Press ENTER.
3. Use the ARROW buttons to display the appropriate option: Off,
Soft, Normal (default), Aggressive or Max. Press ENTER to
activate your selection.
4. Press ESC to return to the previous menu level.
EC TRAIN
Once mics and monitors are positioned in the studio and the levels are set
on the mixing board, the DH30 should be trained to electronic and
acoustic echo.
Training the DH30 — Select Echo Canceller/EC Train in the LCD
display. The display shows both the Echo Return Loss (ERL) and the
current Echo Cancellation (EC).
1. Place a call and route it through the DH30, or have someone
call in. If echo is present, continue with steps 2–7.
2. Select EC Train from the Echo Canceller menu and press
ENTER. This sends a constant burst of white noise out of the
CALLER OUT output. The EC Train uses this white noise to
monitor how much noise comes back to the DH30 through the
acoustic and electronic environment.
3. View the ERL reading on the DH30 LCD display. The ERL
should be at a reading of 0 or below.
4. If the reading is in the positive, decrease the speaker monitor
level and/or the caller audio level of the program mix until the
ERL reading is 0 or lower.
5. Press Esc. This stops the white noise.
6. Have the person on the other end of the telephone line tell you
if an echo is present.
7. If an echo is heard, go back to step one and readjust your
levels for an even lower reading OR adjust the amount of echo
reduction (see the previous section “Echo Reduction” ).
20
DH30 Product Manual
DIAGNOSTICS
The diagnostics feature is used to troubleshoot echo. This feature gives you
the real time and average readings for:
TERL—Telephone Echo Return Loss
TEC—Telephone Echo Cancellation
TNLR—Telephone Non Linear Processing
AERL—Acoustic Echo Return Loss
AEC—Acoustic Echo Cancellation
ANLR—Acoustic Non Linear Processing
The Telephone Diagnostic Bits (TDB) and Acoustic Diagnostic Bits (ADB)
readings are reserved for technical support troubleshooting.
To view these readings:
1.
2.
3.
4.
5.
Use the ARROW buttons to display Echo Canceller. Press ENTER.
Select Diagnostics. Press ENTER.
Use the ARROW buttons to select the desired readout.
Press ENTER to generate a test signal.
Press ENTER to cycle through Receive, Transmit, and Receive
and Transmit test signals.
Note: When generating tones during the diagnostic, you must scroll
through all three readouts before the test signal ceases. Pressing Esc will
take you out of the diagnostic, but will not stop the test signal.
TEST SIGNAL
When configuring your DH30, you can send a test signal through the
monitor (Receive), through the telephone line (Transmit) or through both.
1.
2.
3.
4.
5.
Use the ARROW buttons to display Echo Canceller. Press ENTER.
Use the ARROW buttons to select Test Signal. Press ENTER.
Use the ARROW buttons to select Receive, Transmit or Both.
Press ENTER to send the test signal.
To stop the signal, use the ARROW buttons to select Off.
Press ENTER.
21
Comrex Corporation
SECTION 5.
SETTING CALLER PROCESSING
CUSTOMIZING YOUR SYSTEM
The Caller Processing menu category in the LCD panel includes six
submenu items for controlling various facets of the caller audio.
EQ (Equalizer) — The equalizer function is used to modify the tonal
quality of the caller audio. The basic function is a simple three-band
graphic equalizer. The adjustments to each band determine how much
adjustment is made to the caller audio signal.
When active, the graphic caller equalizer will have the following
characteristics:
• LowBand = 250 Hz – 715 Hz
• MidBand = 715 Hz – 1,645 Hz
• HiBand = 1,645 Hz – 3,500 Hz
Adjustment in each band is from -12 to +12 dB.
Amplitude
400
250
1000
715
2500
1645
3500
Frequency
Compressor — The function of the compressor is to keep the caller
output at the same level regardless of the incoming level. The caller level
should be set to accommodate the quiet callers. The DH30 compresses, or
attenuates, the louder levels.
The compressor works in conjunction with its threshold setting. The
threshold setting is the level at which compression will begin. The ratio
determines the attenuation applied to levels above threshold.
22
DH30 Product Manual
For example, a 2:1 ratio means that for every 2 dB the caller is above
threshold, the audio level will increase only 1 dB. The larger the ratio, the
more compression is applied. The limiter setting keeps the level from
exceeding the threshold. The bypass setting disables the compressor.
v
Ratio options are: Bypass, 2:1, 3:1, 4:1, 6:1 and Limiter.
v
Threshold is referenced to the level of the caller audio on the
VU meter. Adjustable from –20 dBu to 20 dBu.
v
Post gain adds gain to all audio to compensate for compression.
Adjustable from 0 to 20 dB.
v
Attack sets the time required to compress when audio exceeds
threshold. Adjustable from <1 to 50 ms.
v
Release sets the time required to release compression when
audio falls below threshold. Adjustable from 100 ms to 2000 ms
(2 seconds).
Expander (Downward expander) — The expander reduces telephone
line noise when the caller is not talking by decreasing audio gain when
caller audio falls below the threshold level. As long as the caller audio
remains above the threshold, the expander function remains at unity gain
(no expansion). When the caller audio sample drops below the expander
threshold, the expander function decreases the gain by the ratio
determined at setup. Note: If the expander threshold is set too high, the
DH30 may treat the caller as noise. This results in downward expansion
of caller audio.
The expander has the following characteristics:
v
Expansion ratio is adjustable in the following ratios: Bypass,
2:1, 3:1, 4:1 or 6:1.
v
Threshold is referenced to the caller out level.
Adjustable from –50 dBu to 0 dBu.
v
Expansion attack time adjustable from <1 to 50 ms.
v
Expansion release time adjustable from 100 ms to 2000 ms
(2 seconds).
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Comrex Corporation
Bass Boost — Boosting the bass gives a fuller sound to the caller’s audio
by enhancing frequencies below 250 Hz. The front panel LCD program
allows you to adjust the Bass Boost feature over a range of 0 to 10, with 10
being most enhanced. Note: If you have increased the bass in the Caller
Processing menu, you may need to add echo reduction to compensate.
Caller Control — Caller control allows the talent to talk over the caller,
reducing caller audio whenever send audio is present. When send audio is
present, the caller will attenuate/duck by the amount adjusted. You can
adjust the amount of caller attenuation provided, from 0 to -30 dB. A typical
setting would be –6 to –12 dB.
Noise Burst — If activated, a momentary noise burst will be sent to the
telephone line when turning the hybrid on. The noise burst allows the DSP
to adapt the telephone echo canceller and provides a better null at the
beginning of the call. Without the noise burst, the DSP may add attenuation
on the caller audio until the DSP has adapted to an acceptable null.
The trade-off in setting noise burst on is that the caller hears a momentary
noise burst, but the telephone audio is immediately adapted. Setting the
noise burst off spares the caller the brief noise, but the DH30 may require 5
to 20 seconds to adapt.
Training the Telephone Echo Canceller
To retrain a connection to a telephone line, momentarily press
the ON button after the hybrid is already connected to the
telephone line. This initiates the same noise burst mentioned
above and retrains the hybrid.
24
DH30 Product Manual
SYSTEM PARAMETERS
These parameters control the telephone connect and disconnect modes,
remote control switching mode, quality of audio sent to the AUX OUT jack,
sample rate for equipment synchronization, passcode protection, notice of
the firmware version level and the panel locking feature.
Activating Auto Answer — In the auto-answer mode, the DH30
automatically answers telephone calls after one complete ring. Upon
answering, the red OFF LED goes out and the green ON LED comes on. The
call is routed through the digital hybrid and its connection to the console.
1. Select Auto Answer from the system menu and press ENTER.
2. Use the ARROW buttons to select On.
3. Press ESC to exit the function.
Activating Auto Disconnect — When the call is terminated, the digital
hybrid senses the hang up and automatically turns the digital hybrid off.
The green ON LED goes out and the red OFF LED comes on. The DH30
disconnects on all reorder tones with a cadence. Auto disconnect may not
function as described with some PBX systems. Problems in auto-answer
mode may be caused by ring timing. Also, some PBX systems do not
provide loop drop or loop reversal when disconnecting calls. If your PBX
only provides reorder tone or busy signals, the call-progress function must
be enabled for auto-disconnect to function properly.
1. Select Auto Disconnect from the system menu and press ENTER.
2. Use the ARROW buttons to select the signal type the DH30
must detect before disconnecting the call: Loop Drop Only,
Call Progress Only or Loop Drop+CP.
3. Press ESC to exit the function.
Remote Control — DH30 on and off functions can be remotely controlled
by momentary or latching switches. To change the setting, select Remote
Control from the system menu and press ENTER. Then select Momentary
or Latching and press ENTER.
25
Comrex Corporation
Momentary
If you prefer to use a momentary switch to remotely control the DH30,
select Momentary in the Remote Control menu. Pins 1 and 2 when
shorted to ground, will remotely turn the DH30 on and off respectively.
Note: The RECORD and CUE functions can only be activated by momentary
closures. See Section 7 on pages 31-32 for pinout information.
Momentary Switch
DH30 Remote Port
1
On
2
Off
5
Gnd
Latching
If you prefer to use a single switch to remotely control the DH30, then
select Latching in the Remote Control menu.
Latching Switch
DH30 Remote Port
1
On
26
5
Gnd
DH30 Product Manual
Remote Aux Pins — This feature offers pin reassignment to the
preset/mute audio pins. When Mute Audio is selected — Mute Caller
mutes the caller audio, Mute Monitor mutes the monitor output, and
Mute Send mutes the send audio. When Select Presets is selected, you
can choose between three user-programmed settings by activating the
associated preset pin. See Section 7 on pages 31-32 for pinout
information.
Send to Aux — This option determines the type of send audio that goes
to AUX OUT and AES/EBU SEND output. Audio types include Off, Processed
(echo cancelled and bandwidth limited), and Full (full bandwidth and not
echo cancelled). If Mix-Minus/AEC is on, then Send to Aux must be Off
or Processed.
AES/EBU Sample Rate — A 32 kHz internal digital sample rate is
supported by the DH30 (view the rate through the LCD panel). This
sample rate will follow the sample rate of the external AES/EBU equipment
connected to the DH30 AES/EBU input. Digital audio and analog audio are
always operational simultaneously on the hybrid.
Set Passcode — The DH30 passcode can be user programmed. The
default passcode is ppqqENTER.
1. Use the ARROW buttons to display System. Press ENTER.
2. Use the ARROW buttons to display Passcode. Press ENTER.
3. You will be prompted for a new five character passcode.
The q, p, ESC, or ENTER keys are valid passcode keys.
4. Once you enter the new passcode, you will be prompted
to verify the passcode.
5. If you enter the new passcode incorrectly, Mismatch will
appear and you will have to begin again.
If you enter it correctly, Passcode Changed will appear and
the new passcode will be activated.
Version — Displays current operating version of the DH30.
Lock Panel — Toggles the lock on/off. You will need to enter the
passcode to lock or unlock the panel controls. When the panel is locked,
the user can select presets but cannot change the parameters of the
presets. To verify that the panel is locked, an ‘L’ will appear in the bottom
right corner of the LCD display.
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Comrex Corporation
SECTION 6.
SPECIFICATIONS
DIMENSIONS
17.125”/43.5cm W x 1.75”/4.44cm H x 10.125”/25.7cm D
Rackmount included for installation in a 19” rack
WEIGHT
6.7lbs/3.04kg (dry)
11.2lbs/5.08kg (shipping)
OPERATING TEMPERATURE
32-100°F/0-38°C
0-80% - Humidity
FRONT PANEL CONTROLS
LCD programming display, ENTER/ESC/pq programming buttons, monitor
volume control, send-level LED bar meter, caller-level LED bar
meter, record, cue, hybrid ON/OFF, buttons with status LEDs
REAR PANEL CONNECTORS
POWER: IEC Type
Auto Adjusting, 100-240VAC, 2A, 50/60Hz, 30W
AES/EBU IN: XLR
pin 1= ground, pin 2= +phase, pin 3= -phase;
32, 44.1, or 48kHz sample rate
AES/EBU OUT: XLR
pin 1=ground, pin 2=+phase, pin 3= -phase;
32, 44.1, or 48kHz sample rate
RS232: DB9 female connector
9,600 baud rate, used for status and control via a PC or
other RS232 controller
RECORD CONTROL: DB9 female
Start, stop, and enable outputs are open collector outputs rated at
40VDC and 50mA maximum
REMOTE: DB25 female
Remote Send Input:
0dBu nominal, adjustable, unbalanced, 20k Ohm impedance
Remote Caller and Aux Outputs:
0dBu nominal, adjustable, unbalanced, 50k Ohm impedance
28
DH30 Product Manual
Control Inputs:
Remotely activate any of the following functions with a
simple switch closure to ground: ON, OFF, CUE and REC
along with preset selection controls 1,2 and 3 or with
send, caller, and monitor mute controls.
Status Outputs:
Remotely check the status of the hybrid with the ON, OFF,
CUE, REC, send presence and caller presence status
outputs. All status outputs are open collector outputs rated
at 40VDC and 50mA maximum.
MONITOR OUTPUT: 1/4” stereo jack
tip=+phase, ring=-phase, sleeve=-phase
2W output into an 8 Ohm load
SEND INPUT: XLR female
Mic/Line selectable, -55 or 0dBu nominal, adjustable, balanced
bridging, 20k Ohm impedance, selectable 12VDC Phantom Power
CUE IN: XLR female
Mic/Line selectable, -55 or 0dBu nominal, adjustable, balanced
bridging, 20k Ohm impedance, selectable 12VDC Phantom Power
CALLER OUTPUT: XLR male
0dBu nominal, adjustable, balanced 50k Ohm impedance
AUX OUTPUT: XLR male
0dBu nominal, adjustable, balanced 50k Ohm impedance
TELCO LINE: RJ11 connector
POTS (plain old telephone service) line or analog extension from a
PBX or dry line (no DC offset voltage). A-Lead supervision provided
(see “Line Connector” pinout chart on page 32 for further details).
TELCO SET: RJ11 connector
A-Lead supervision provided (see “Set Connector” pinout chart on
page 32 for further details).
TELEPHONE TRANSMIT
All measurements referenced at –15dBm level on the phone line.
FREQUENCY RESPONSE: +/- 1dB from 250Hz to 3.5kHz
SIGNAL TO NOISE: >70dB
DISTORTION: <0.15%
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Comrex Corporation
30
TELEPHONE RECEIVE
All measurements referenced at –15 dBm level on the phone line with
caller processing options bypassed.
FREQUENCY RESPONSE: +/- 1dB from 250Hz to 3.5kHz
SIGNAL TO NOISE: >70dB
DISTORTION: <0.1%
ECHO CANCELLATION/MIXMINUS
TAIL TIME: 120 milliseconds
NULL: 50dB
TELCO CANCELLATION
TAIL TIME: 32 milliseconds
NULL: 55dB
DH30 Product Manual
SECTION 7.
PINOUTS
REMOTE CONNECTOR
Pin
1
Description
Remote on *
Pin
14
2
Remote off *
15
Remote off Indication **
3
Remote Record *
16
Record Indication **
4
Remote Cue *
17
Cue Indication **
5
Switch/Indicator Common
18
Indicator Common
†6
Select Preset 1/Send Mute *
19
Send Presence Indicator **
†7
Select Preset 2/Caller Mute *
20
Caller Presence Indicator **
8
N/C
21
9
Unbalanced Send #
22
10
Unbalanced Caller ##
23
11
Unbalanced Aux Out ###
24
Indicator Common
Unbalanced
Audio Common #
Unbalanced
Audio Common ##
Unbalanced
Audio Common ##
Select Preset 3/Monitor Mute*
25
Switch Common
† 12
*
**
#
##
†
RS232 CONNECTOR
Description
Remote on Indication **
13
N/C
Remote control provided via contact closure to digital ground
Remote indicators provided via open collector outputs, <40 V, 50 mA
0dB line-level input with >20 kOhm impedance
0dB line level output with a <50 Ohm impedance
These control inputs will perform preset selection or audio path muting as set by the system menu selection of Remote aux pins
Pin
Description
Pin
Description
1
N/C
6
N/C
2
TXD
7
N/C
3
RXD
8
N/C
4
N/C
9
N/C
5
GROUND
31
Comrex Corporation
RECORD CONTROL
LINE CONNECTOR
Pin
Description
Pin
Description
1
Start
6
Start Common
2
N/C
7
N/C
3
N/C
8
Stop Common
4
Stop
9
Record Enable Common
5
Record Enable
Pin
Description
Pin
Description
1
To pin 6 of SET RJ11C
4
*2
To pin 5 SET of RJ11C
*5
To pin 2 of SET RJ11C
6
To pin 1 of SET RJ11C
3
Tip
Ring
*When the ON button is illuminated on the DH30, an “A-Lead Closure” is
provided between pins 2 and 5 of the LINE and SET jacks. This connection is
useful for key telephone system such as the 1A2. If you connect the DH30 to
an extension jack of a more modern PBX, you should first check to see if
those wires are used for signalling or power. If so, do not connect them to
the DH30. You may, however, use the pin 2-5 connection to control the
hookswitch on a modified PBX phone. Contact Comrex technical support for
more information.
SET CONNECTOR
Pin
32
Pin
Description
1
To pin 6 of LINE RJ11C
4
*2
To pin 5 of LINE RJ11C
*5
To pin 2 of LINE RJ11C
6
To pin 1 of LINE RJ11C
3
XLR CONNECTOR
Description
Pin
Ring
Description
1
Ground
2
3
Pin
Tip
Description
Tip
+ Phase audio
+ Phase audio
Ring
- Phase audio
- Phase audio
Sleeve
- Phase audio
DH30 Product Manual
SECTION 8.
SERIAL COMMUNICATIONS PROTOCOL
The RS232 port on the DH30 is a serial communications port used to
control DH30 operations through an external device such as a PC or a
control device. This section describes the protocol and serial commands
used to control the DH30.
The RS232 serial port runs at 9600 baud, no parity, eight data bits and one
stop bit.
Serial commands to the DH30 can control the following types of
operations: Hybrid On/Off, Cuing, Recording, Monitor volume, Preset
selection and Detection of an Incoming Call.
Function
Serial Command
Returned Status
On/Off
Off
On
TE<cr>
TE 0<cr>
TE 1<cr>
TE 0<cr> or TE1<cr>
TE 0
TE 1
Cue Status
Cue Off
Cue On
Cue Toggle
CUE<cr>
CUE 0<cr>
CUE 1<cr>
CUE 2<cr>
CUE 0 or CUE 1
CUE 0
CUE 1
CUE 0 or CUE 1
(toggled)
Record Status
Record Off
Record On
Record Toggle
REC<cr>
REC 0<cr>
REC 1<cr>
REC 2<cr>
REC 0/1/2/3
(see note below)
Monitor Volume Up*
Monitor Volume Down
* no value given
VOLUP<cr>
VOLDWN<cr>
VOLUP
VOLDWN
Current Preset
Select Preset 1
Select Preset 2
Select Preset 3
PRESET<cr>
PRESET 1<cr>
PRESET 2<cr>
PRESET 3<cr>
PRESET 1
PRESET 2
PRESET 3
Incoming Call
N/A
RING
NOTE: The returned status is dependent on the current setting of the hybrid. See the table below:
Status Returned
0
1
2
3
Record-Ready
no
yes
no
yes
Recording
no
no
yes
yes
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Comrex Corporation
The structure of serial commands is an option/value, followed by a
carriage return:
command x
Commands can be either UPPER CASE or lower case terminated by a
carriage return. Characters are not echoed back to the sending device as
they are sent. After a command has been sent, including the carriage
return, the command is echoed back in uppercase with the new value
followed by a DH30> command prompt.
For example, a command to turn Cue on would be formatted like this:
CUE 1<cr>
(CUE =function command, 1=On, as shown in the facing table.)
The returned response would be:
CUE 1
DH30>
If the Cue feature was off and the toggle Cue command was sent:
CUE 2<cr>
The returned response would be:
CUE 1
DH30>
Indicating that the Cue feature had been turned on.
To get status back on what the current setting is, send the command
without a parameter. For example if the Cue function is on when the
command is sent:
CUE<cr>
The response would be:
CUE 1
DH30>
34
DH30 Product Manual
SECTION 9.
DH30 AUDIO FLOW
The diagram below shows all the audio inputs and outputs and associated
gain blocks and mixing junctions. The inputs are on the left (however, the
Telco LINE and SET jacks are both input and output). The outputs are on
the right.
DH30 Audio Flow
Mic/Line
Send to Aux
Send In
(XLR)
Off
Send In
Send In
Gain
(DB25 Pin 9)
+/-20
Aux Send
Full
Gain
Bandwidth
Aux Out
+/-20
(XLR)
Processed
Gain
Aux Out
+/-20
AES/EBU In
AES/
(XLR)
EBU
Send (left)
Aux Call
Cue (right)
Send (right)
Cue
Mic/Line
Cue In
(XLR)
(DB25 Pin 11)
Cue In
button
Caller (left)
AES/
EBU
AES/EBU Out
(XLR)
Gain
+/-20
Caller Out
(XLR)
Telco Line
(RJ-11)
Send
Caller Out
Processing
Call Out
Monitor
Volume
Caller
Gain
Processing
+/-20
Gain
+18
Telco Set
(RJ-11)
(DB25 Pin 10)
to mute
2W
Amp
Monitor
(1/4" Phono)
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Comrex Corporation
SECTION 10.
FCC PART 15 COMPLIANCE
COMPLIANCE
This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC rules. These limits are
designed to provide reasonable protection against harmful interference
when the equipment is operated in a commercial environment. This
equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful
interference, in which case the user will be required to correct the
interference at his/her own expense.
Changes or modifications not expressly approved by Comrex Corporation
could void the user’s authority to operate the equipment.
FCC PART 68 COMPLIANCE
A label containing the FCC registration number and Ringer Equivalence
Number (REN) for this equipment is prominently posted on the top plate
near the rear of the equipment. If requested, this information must be
provided to your telephone company.
USOC Jacks: This device uses RJ11C and RJ21X terminal jacks.
The REN is used to determine the quantity of devices which may be
connected to the telephone line. Excessive REN’s on the telephone line
may result in the devices not ringing in response to an incoming call. In
most, but not all areas, the sum of the REN’s should not exceed five (5). To
be certain of the number of devices that may be connected to the line, as
determined by the total REN’s, contact the telephone company to obtain
the maximum REN’s for the calling area.
If this equipment causes harm to the telephone network, the telephone
company will notify you in advance that temporary discontinuance of
service may be required. If advance notice is not practical, the telephone
company will notify the customer as soon as possible. Also, you will be
advised of your right to file a complaint with the FCC, if you believe it is
necessary.
The telephone company may make changes in its facilities, equipment,
operations or procedures that could affect the operation of the equipment.
If this happens, the telephone company will provide advance notice for
you to make the necessary modifications in order to maintain
uninterrupted service.
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DH30 Product Manual
If you experience problems with this equipment, contact Comrex
Corportation, 19 Pine Road, Devens, MA 01432 or by telephone at 978784-1776 for repair and warranty information. If the trouble is causing
harm to the telephone network, the telephone company may request you
remove the equipment from the network until the problem is resolved.
No user serviceable parts are contained in this product. If damage or
malfunction occurs, contact Comrex Corporation for instructions on its
repair or return.
This equipment cannot be used on telephone company provided coin
service. Connection to Party Line Service is subject to state tariffs.
IC COMPLIANCE
NOTICE: The Industry of Canada label identifies certified equipment. This
certification means that the equipment meets certain telecommunications
network protective operational and safety requirements. The Department
does not guarantee the equipment will operate to the user’s satisfaction.
Before installing this equipment, users should ensure that it is permissible
to be connected to the facilities of the local telecommunications company.
The equipment must also be installed using an acceptable method of
connection. In some cases, the company’s inside wiring associated with a
single line individual service may be extended by means of a certified
connector assembly (telephone extension cord). The customer should be
aware that compliance with the above conditions may not prevent
degradation of service in some situations.
Repairs to certified equipment should be made by Comrex Corporation.
Any repairs or alterations made by the user to this equipment, or
equipment malfunctions, may give the telecommunications company
cause to request the user to disconnect the equipment.
Users should ensure, for their own protection, that the electrical ground
connections of the power utility, telephone lines, and internal metallic
water pipe system, if present, are connected together. This precaution may
be particularly important in rural areas.
CAUTION: Users should not attempt to make such connections
themselves, but should contact the appropriate electrical inspection
authority, or electrician, as appropriate.
37
Comrex Corporation
INTERNATIONAL COMPLIANCE
(APPLIES TO
DH30 910-012-302)
Information for CTR21
The Digital Hybrid 30/DH30/910-012-302 has been approved in accordance
with Council Decision 98/482/EC for pan-European single terminal
connection to the public switched telephone network (PSTN). However,
due to differences between the individual PSTN’s provided in different
countries, the approval does not, of itself, give an unconditional assurance
of successful operation on every PSTN network termination point.
In the event of problems, you should contact your equipment supplier in
the first instance.
Network Compatibility Declaration
Comrex Corporation, 19 Pine Road, Devens, MA 01432 USA declares that
the product Digital Hybrid 30/DH30/910-012-302 is designed to be
compatible with the following networks: Austria, Belgium, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland, Italy, Liechtenstein,
Luxembourg, The Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and United Kingdom.
38
DH30 Product Manual
SECTION 11.
USER-DEFINED PRESETS WORKSHEET
Use these worksheets to record the presets you configure for your site. For
descriptions of the menu options, refer to “Viewing or Changing Settings”
through the LCD Panel on page 17.
Menu
Categories
Presets
Gain
Submenu
Selections
Submenu
Parameters
Submenu
Ranges
Select Preset
Factory
Default
User
Preset 1
User
Preset 2
User
Preset 3
Preset 1
Copy Preset
n/a
Recall Default
n/a
Send In Gain
-20 to 20dB
0dB
Send In Preamp
Line
Line
Mic
Cue In Gain
-20 to 20dB
0dB
Cue In Preamp
Line
Line
Call Out Gain
-20 to 20dB
Mic
Caller
0dB
Aux Send Gain
-20 to 20dB
0dB
Aux Call Gain
-20 to 20dB
0dB
Off
On
EQ
EQ Bypass
On
Compressor
EQ Low Band
-20 to 20dB
0dB
EQ Mid Band
-20 to 20dB
0dB
EQ High Band
-20 to 20dB
0dB
Comp Ratio
Bypass
Bypass
2:1
3:1
4:1
6:1
Limiter
Expander
Comp Threshold
-20 to 20dB
Comp Post Gain
-20 to 20dB
0dB
0dB
Comp Attack
<1mS to 50mS
15mS
Comp Release
100 to 2000mS
500mS
Exp Ratio
Bypass
Bypass
2:1
3:1
4:1
6:1
Exp Threshold
Bass Boost
-50 to 0dB
-40dB
Exp Attack
<1mS to 50mS
15mS
Exp Release
100 to 2000mS
500mS
0 to 30
0
Caller Control
0 to -30dB
0dB
Noise Burst
Off
On
On
39
Comrex Corporation
Menu
Categories
Echo
Canceller
Submenu
Selections
Mix-minus/AEC
Submenu
Parameters
Submenu
Ranges
Off
Factory
Default
User
Preset 1
User
Preset 2
User
Preset 3
On
On
Echo Reduction
Off
Normal
Soft
Normal
Aggressive
Maximum
EC Train
Off
Off
On
Diagnostics
Off
Off
TERL
TEC
TNLP
TDB
AERL
AEC
ANLP
ADB
Test Signal
Off
Off
Receive
Transmit
Rcv & Transmit
System
Auto Answer
Off
Off
On
Auto Disconnect
Off
Off
Loop Drop Only
Call Prog Only
Loop Drop + CP
Remote Control
Momentary
Momentary
Latching
Remote Aux Pins
Mute Audio
Select Presets
Select Presets
Send to Aux
Off
Processed
Processed
Full bandwidth
AES/EBU
32000 Internal
32000 Internal
*32000 External
*44100 External
*48000 External
Set Passcode
New Passcode
Version**
Lock Panel
ppqq
Enter
Vx.x Date
Off
Off
On--"L" will appear in lower right corner of screen
*The DH30's AES/EBU sample rate wil default to 32000 internal, until the AES/EBU input is connected.
Once connected, the DH30 will follow the sample rate of the external AES/EBU equipment.
**Sub menu version will indicate the current version of code and the date implemented.
40
DH30 Product Manual
SECTION 12.
GLOSSARY
AES/EBU — Audio Engineering Society/European Broadcasting Union. The
protocol for communicating two-channel digital audio information over a
serial link.
AEC — Acoustic Echo Cancellation. The process of removing echo before it
returns to its source.
AERL — Acoustic Echo Return Loss. The amount of echo returned to the
audio source in an acoustic environment.
Analog Line — A telephone line that is not digital.
Balanced Audio — A two-line audio signal without reference to ground
(i.e. differential-mode audio).
Bass Boost — Spectral enhancement of frequencies below 250 Hz.
Bypass — A route where current flows around instead of through a
component or circuit.
Cadence — Any tone on a telephone line that has a distinct pattern.
Call Progress Tones — Tones sent from the telephone switch to inform
the caller or devices that a call has ended. These tones include a busy
signal, dial tone, fast busy, or dual-tones.
Caller — The caller’s voice as it enters the hybrid from the telephone line.
Caller Control — Suppression of caller audio when send audio is present.
Compressor — See Limiter.
Console — The audio mixer used to combine all programming sources. A
console is also called a mixing board, a mixer, audio board, etc.
Cue — Audio heard by caller when cue mode is active.
Digital Signal Processing — Digitally modifying a signal to provide a
specific function or output.
Dryline — A telephone circuit over which voice signals are transmitted and
contains no DC offset voltage.
41
Comrex Corporation
DSP — Digital Signal Processing/Processor.
Echo Cancellation — Digital removal of speaker audio that is picked up by
the microphone.
Equalizer — A device that allows the user to tailor frequency response.
Expander — More accurately called the downward expander, this
suppresses noise when the caller is not talking.
Handset — The hand-held part of a communications system, usually
consisting of a speaker and microphone.
Hybrid — See Telephone Hybrid.
Latching — A control signal that remains in a fixed state until you release it.
This is opposed to momentary control, which is a pulsed signal.
LED — Light emitting diode. A semiconductor diode used in an electronic
display that emits a light when subjected to an applied voltage.
Limiter — A circuit whose output signal amplitude remains at a
predetermined level despite variations in input signal amplitude.
Loop Drop — A temporary interruption on the telephone line’s DC voltage.
Mix-Minus — Audio that must be sent to callers to prevent feedback on the
audio system through the hybrid. Mix-Minus is a mix of all audio on the
console, minus the caller’s audio. Without a mix-minus feed, the caller
audio appearing on the console is sent back to the caller, where it is
retransmitted to the studio through the caller’s telephone. This feedback
can create anything from an echo to a howling squeal.
Noise Burst — A burst of white noise used by the hybrid to optimize echo
cancellation and null performance.
Null — The ability of the analog hybrid to separate send audio from caller
audio. (Also known as trans-hybrid loss or side tone.)
Off — The DH30 front panel control that disconnects callers who are active
on the system. This control does not affect DH30 power.
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DH30 Product Manual
On-Air — Callers are put on-air with the announcer so the listening
audience can hear the conversation.
PBX — Private Branch Exchange. See Telephone Line.
Phantom Power — Power provided by audio equipment to power
microphones that contain active components. This provides a DC offset
voltage to the signal.
Pinouts — Configuration of signal-carrying lines on a connector.
Send — Refers to audio sent to the caller from the studio mixer or
microphone.
TEC — Telephone Echo Cancellation. The process of removing echo
before it returns to its source over a telephone line.
TERL — Telephone Echo Return Loss. The amount of echo returned to
the audio source over a telephone line.
Telephone Hybrid — A device that converts a telephone line (2-wire,
low-level signal) into a balanced, 4-wire, line-level signal with independent
send and receive ports. A telephone hybrid provides the necessary
electronic matching between the telephone line and the audio
equipment. Generally referred to in this manual as simply “hybrid.”
Telephone Line — The line delivered by the telephone company to an
individual subscriber. Sometimes known as a POTS (Plain Old Telephone
Service) line, this is an analog line required by fax machines and modems.
The DH30 requires analog telephone lines for its phone line connection.
PBX systems or other digital telephone systems must be equipped with an
analog extension for use with the DH30.
Threshold — A predetermined point for the start of operation of a circuit.
Unbalanced Audio — A circuit that is referenced to ground.
Wet Line — A telephone circuit over which voice signals are transmitted
and contains DC offset voltage.
43
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