DH30 D

IGITAL

T

ELEPHONE

H

YBRID

T

ABLE OF

C

ONTENTS

S

ECTION

1 .........I

NTRODUCTION

......................................................................................... 4

........................W

HAT IS A

H

YBRID

? ...................................................................... 4

........................DH30 F

EATURES

........................................................................ 4

........................W

HAT

C

OMES WITH THE

DH30? .................................................... 6

........................P

RODUCT

R

EGISTRATION AND

T

ECHNICAL

S

UPPORT

.............................. 6

........................O

PERATIONAL

R

EQUIREMENTS

.......................................................... 7

S

ECTION

2..........C

ONNECTING THE

E

QUIPMENT

..................................................................... 8

........................T

YPICAL

DH30 D

IGITAL

I

NSTALLATION

.............................................. 8

........................C

ONSOLE

C

ONNECTIONS

— D

IGITAL

A

UDIO

...................................... 8

........................T

YPICAL

DH30 A

NALOG

I

NSTALLATION

.............................................. 9

........................C

ONSOLE

C

ONNECTIONS

— A

NALOG

A

UDIO

...................................... 9

........................A

DDITIONAL

C

ONNECTIONS

............................................................. 10

S

ECTION

3..........S

ETUP AND

O

PERATION

.............................................................................. 12

........................F

RONT

P

ANEL

C

ONTROLS

............................................................... 12

........................H

ANDLING

C

ALLS

......................................................................... 14

........................R

ECORDING

C

ALLS

........................................................................ 15

........................U

SING THE

N

AVIGATING

B

UTTONS AND

A

DJUSTING

P

ARAMETERS

............... 16

........................V

IEWING OF

C

HANGING

S

ETTINGS

T

HROUGH THE

LCD P

ANEL

................ 17

........................U

SING

P

RESETS

............................................................................ 18

........................S

ETTING

L

EVELS

........................................................................... 18

S

ECTION

4..........A

UTO

M

IX

-M

INUS AND

A

COUSTIC

E

CHO

C

ANCELLATION

..................................... 19

........................M

IX

-M

INUS

/A

COUSTIC

E

CHO

C

ANCELLATION

...................................... 19

........................E

CHO

R

EDUCTION

........................................................................ 20

........................EC T

RAIN

.................................................................................. 20

........................D

IAGNOSTICS

............................................................................... 21

........................T

EST

S

IGNAL

............................................................................... 21

S

ECTION

5..........C

USTOMIZING

Y

OUR

S

YSTEM

....................................................................... 22

........................S

ETTING

C

ALLER

P

ROCESSING

......................................................... 22

........................S

YSTEM

P

ARAMETERS

..................................................................... 25

S

ECTION 6..........S

PECIFICATIONS

....................................................................................... 28

........................D

IMENSIONS

............................................................................... 28

........................W

EIGHT

.................................................................................... 28

........................O

PERATING

T

EMPERATURE

.............................................................. 28

........................F

RONT

P

ANEL

C

ONTROLS

............................................................... 28

........................R

EAR

P

ANEL

C

ONNECTORS

.............................................................. 28

........................T

ELEPHONE

T

RANSMIT

................................................................... 29

........................T

ELEPHONE

R

ECEIVE

..................................................................... 30

........................E

CHO

C

ANCELLATION

/M

IX

-M

INUS

.................................................... 30

........................T

ELCO

C

ANCELLATION

.................................................................... 30

2

Comrex Corporation

T

ABLE OF

C

ONTENTS

(

CONT

.)

S

ECTION

S

ECTION

S

ECTION

S

ECTION

S

S

ECTION

ECTION

7 .........P

INOUTS

................................................................................................ 31

........................R

EMOTE

C

ONNECTOR

................................................................... 31

........................RS232 C

ONNECTOR

..................................................................... 31

........................R

ECORD

C

ONTROL

........................................................................ 32

........................L

INE

C

ONNECTOR

......................................................................... 32

........................S

ET

C

ONNECTOR

.......................................................................... 32

........................XLR C

ONNECTOR

......................................................................... 32

8..........S

ERIAL

C

OMMUNICATIONS

P

ROTOCOL

............................................................. 33

9..........DH30 A

UDIO

F

LOW

................................................................................ 35

10........C

OMPLIANCE

........................................................................................... 36

............ ............

FCC P

ART

15 C

OMPLIANCE

.......................................................... 36

........................FCC P

ART

68 C

OMPLIANCE

.......................................................... 36

........................IC C

OMPLIANCE

.......................................................................... 37

........................I

NTERNATIONAL

C

OMPLIANCE

.......................................................... 38

11........U

SER

-D

EFINED

P

RESETS

W

ORKSHEET

............................................................ 39

12........G

LOSSARY

............................................................................................... 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 01434 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

S

ECTION

I

NTRODUCTION

4

W

HAT IS A

H

YBRID

?

DH30 F

EATURES

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.

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:

• Selectable auto mix-minus and acoustic echo cancellation, allowing for operation in a variety of closed or open studio environments.

DH30 Product Manual

• Programmable auto-answer, auto-disconnect and caller control functions.

• Call monitoring capability with a built-in 2-watt monitoring amplifier and front-panel volume control.

• AES/EBU connections allow for a direct digital au dio link between the

DH30 and a digital console.

• Analog connections are made using the send and cue inputs and the caller and aux outputs.

• Each input and output has its own adjustable gain control, ensuring the best audio mix in ev ery application.

• 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.

• 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.

• 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.

• 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.

5

6

Comrex Corporation

W

HAT

C

OMES WITH THE

DH30?

Enter Esc

Volume

Send

-36 -24 -12 -3 -4

0

+4 +8

Caller

-36 -24 -12 -3 -4

0

+4 +8

DH30

(Domestic or International)

Rec Cue On Of f

DH30

7-foot Modular

Telephone Cable

Specialists in Remote

Broadcast

Audio

Transmission

DH30

Digital Telephone Hybrid

Product Manual

DH30 Installation and

Operations Manual

AC Power Cord

P

RODUCT

R

EGISTRATION AND

T

ECHNICAL

S

UPPORT

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, 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]

DH30 Product Manual

O

PERATIONAL

R

EQUIREMENTS

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.

7

Comrex Corporation

S

ECTION

C

ONNECTING THE

E

QUIPMENT

T

YPICAL

DH30 D

IGITAL

I

NSTALLATION

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

Telephone Set

Console Out

Console In

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

8

C

ONSOLE

C

ONNECTIONS

— D

IGITAL

A

UDIO

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 I

N

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. In order to enable this input, the AES/EBU sampling rate must be selected in the System Parameters menu.

AES/EBU Out —

This is the output of the callers voice. Connect the AES/EBU

O

UT

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 C

UE

button).

Note: You should cycle power anytime you disconnect AES/EBU connectors from the DH30.

DH30 Product Manual

T

YPICAL

DH30 A

NALOG

I

NSTALLATION

Telephone Line

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

C

ONSOLE

C

ONNECTIONS

— A

NALOG

A

UDIO

Send In —

This is the audio that the caller will hear. Connect a mic or line output from the studio console to the S

END

I

N

input of the DH30.

If the DH30’s echo canceller feature is disabled, you must send mix-minus audio to the S

END

I

N

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 C

UE

I

N

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 C

ALLER

O

UT

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 C

UE

button). Connect the A

UX

O

UT

to an input channel of your studio console or recording device.

The caller/send mix is programmable through the front panel LCD display.

9

10

Comrex Corporation

A

DDITIONAL

C

ONNECTIONS

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

INE

jack.

Set

ET

jack.

REMOTE

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

RECORD CONTROL

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 —

Control a tape deck or other external recording device with this DB9 R

ECORD

C

ONTROL

connector.

This DB9 female connector sends start, stop and enable commands for automatic telephone call recording. This connector provides control only. Use the A

UX

O

UT

connector to route audio to the recording device.

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.

11

Comrex Corporation

S

ECTION

S

ETUP AND

O

PERATION

12

F

RONT

P

ANEL

C

ONTROLS

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.

Enter Esc

Volume

Send

-36 -24 -12 -3 -4

0

+4 +8

Caller

-36 -24 -12 -3 -4

0

+4 +8

Rec Cue On Of f

DH30

On

Rec

Cue

Of f

On and Off —

When the DH30 is plugged in, it defaults with the hybrid off, indicated by the red O

FF

LED.

The O

N

button connects the DH30 to the telephone line and causes the hybrid to adapt to the line. Pressing the O

N

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.

When the O

FF

button is pressed, the DH30 disconnects from the telephone line and mutes caller audio. The red O

FF

LED illuminates.

Record —

The R

EC

button controls the start or stop of an external recording device connected to the DH30 through the R

ECORD

C

ONTROL

output on the rear panel.

The R

ECORD

LED flashes red when recording, appears solid red in recordready (standby) mode and is not lit when record mode is off.

Cue —

The C

UE

button enables the talent to speak to a caller off the air.

When you press the C

UE

button, the C

UE

LED illuminates and audio from the cue input is routed to the caller. When the C

UE

button is off, the C

UE

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.

DH30 Product Manual

Send

-36 -24 -12 -3 -4

0

+4 +8

Caller

-36 -24 -12 -3 -4

0

+4 +8

Volume

Enter Esc

VU Meters (Send and Caller) —

These LED’s indicate the audio levels at the S

END

and C

ALLER

XLR connectors.

The S

END

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 C

ALLER

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 C

ALLER

meter reading.

Volume —

The up and down arrows ( S / T ) raise or lower the volume level of the internal 2-watt power amplifier to the speaker or headphone connected to the M

ONITOR

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 S and T simultaneously will reset the volume to nominal (0 dBu).

Enter, Esc,

S

/

T

—

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.

13

14

Comrex Corporation

H

ANDLING

C

ALLS

Receiving a Call —

To set up the DH30 for automatic answer or disconnect, refer to “System Parameters” (pages 25–26).

• On-Air — When a call rings on the telephone line connected to the DH30, the O

N

LED will flash and the telephone connected to the S

ET

output will ring. Answer the call by pressing the O

N

button or activating the hybrid from your remote console control (if applicable). This routes the call through the hybrid, and the green O

N

LED illuminates. Upon connection, the DH30 automatically adjusts to line conditions.

• Off-Air — Answer the call by picking up the telephone handset and talking to your party over the telephone. Do not press O

N

.

Disconnecting a Call —

If the call is routed through the DH30 (the O

N

LED is lit), press the O

FF

button to disconnect the call. The O

FF

LED illuminates, and the O

N

LED goes out.

Note: If the handset is off hook when the

Off button is pressed, the call er will remain on the handset.

If your call is through the handset only (the red O

FF

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 O

N button. The O

N

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 O

FF

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 O

FF

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.

DH30 Product Manual

R

ECORDING

C

ALLS

The record function controls a recording device through the DB9 R

ECORD

C

ONTROL

connecter. To use the record function, a recording device must be connected to the DB9 R

ECORD

C

ONTROL

connector. The A

UX

O

UT

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 R

ECORD

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 R

ECORD

to begin recording. The LED will flash. When you turn the hybrid off or when you press R

ECORD

again, recording will stop and the LED will go off.

Using Record Ready —

Press R

ECORD

when the hybrid is off. The R

ECORD

LED will illuminate. When the O

N

button is pressed, recording begins automatically and the R

ECORD

LED flashes. When the hybrid is turned off or when you manually press the R

ECORD

button again, recording stops and the R

ECORD

LED becomes steady, indicating record-ready mode is still active.

Note: The O

N

and O

FF

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

16

Comrex Corporation

2 GAIN

SEND IN

Enter Esc

Volume

Send

-36 -24 -12 -3 -4

0

+4 +8

Caller

-36 -24 -12 -3 -4

0

+4 +8

LCD Panel

Rec Cue On Of f

DH30

U

SING THE

N

AVIGATING

B

UTTONS AND

A

D JUST ING

P

ARAMETERS

To scroll through the menu items on the LCD panel, press the U

P

and D

OWN buttons. When a desired menu item is reached, press E

NTER

. Use the U

P

and

D

OWN

buttons to scroll through the parameters. Press E

SC

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 E

NTER

. The parameter will begin to blink, indicating that the U

P

and D

OWN

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 E

NTER

.

This stores the value in the menu and it becomes the new preset value. If you press E

SC

, no changes will be made to the parameter, leaving the original setting as the preset value.

DH30 Product Manual

V

IEWING OR

C

HANGING

S

ETTINGS

T

HROUGH THE

LCD P

ANEL

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 Function Defaults

Presets

Gain

Caller Processing

Select Preset

Copy Preset

Recall Default

Send In

Send Mic/Line

Cue In

Cue Mic/Line

Call Out Gain

Aux Send

Aux Caller

3 Band EQ

Compressor

Expander

Bass Boost

Caller Control

Noise Burst

Store 3 Sets of Unique Configurations that can be Selected

Selects Preset 1, 2, or 3 - loads all parameters associated with selected preset

Copies settings from the active preset into one of the other two presets

Restores settings to factory default for current preset

Set Gain for Inputs and Outputs

Adjusts send audio level as heard by caller

Adjusts send input for mic or line input

Adjusts cue audio level as heard by caller

Adjusts cue input for mic or line input

Adjusts caller's audio level out of DH30

Adjusts send audio level at aux output

Adjusts caller's audio level at aux output

1

N/A

N/A

0dB

Line

0dB

Line

0dB

0dB

0dB

Adjust Audio for Incoming Calls

Adjusts to tonal quality of the caller's voice

Enables DH30 to handle wide range of caller voice levels

Attenuates line or background noise when caller is not talking

Enhances caller bass

Allows talent to talk over caller

Toggles whether or not a noise burst is sent down telephone line when connection to the phone line is made

Bypass

Bypass

Bypass

Bypass

0dB

On

Echo Canceller

System

Adjust Auto Mix-Minus/AEC

Mix-minus/AEC Turns mix-minus/acoustic echo cancellation on/off

Echo Reduction Selects echo reduction enhancement

EC Train

Diagnostics

Test Signal

Trains echo canceller to the room environment (acoustic) or studio (auto mix-minus) during setup

Displays measurements for troubleshooting

Turns on/off noise generator to test receive or transmit

Adjusts Various System Parameters

Auto Answer Turns on/off automatic phone answer on first ring

Auto Disconnect Selects type of auto disconnect

Remote Control Sets remote on pin for momentary or latching control

Remote Auxpins Selects aux pins for preset selection or audio muting control

AES/EBU Enable AES/EBU by selecting a sampling rate

On

Normal

N/A

N/A

Off

Off

Off

Momentary

Select

Presets

Off

Lock Panel

Send to Aux

Set Passcode

Version

On/Off

Selects type of send audio routed to aux output

Sets passcode used to lock and unlock adjustment presets

Displays firmware version of DH30

Processed

SSTT

Enter

N/A

Locks Adjustment of Parameters

Toggles adjustment of presets off and on, offering protection to preset parameters. "L" appears in the bottom right corner of LED screen when locked

Off

17

Comrex Corporation

U

SING

P

RESETS

Preset 1

Preset 2

Preset 3

S

ETTING

L

EVELS

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). 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.

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 O

N

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 A

RROW

keys to locate the appropriate function.

2. Press E

NTER

.

3. Use the A

RROW

buttons to adjust levels. (You can observe S

END

I

N and C

ALLER

O

UT

level changes on the S

END

and C

ALLER

meter LED’s.)

4. Press E

NTER

to save the value into the current-selected preset.

18

Submenu Options Function

Send In Gain

Send Mic/Line Gain

Cue In Gain

Cue Mic/Line Gain

Caller Out Gain

Hints for Setting

The Send In level is set for a nominal input level of 0dB.

This line-level input is adjustable from -20dB to 20dB

Adds 55 dB fixed gain

The Cue In level is set for a nominal input level of 0dB.

This input level is adjustable from -20dB to 20dB

Adjust to select a value that registers

0dB on the Send meter LED

Set to LINE unless you are connecting directly to a microphone

With Cue audio selected, adjust to select a value that registers 0dB on the Send meter LED

Set to LINE unless you are connecting Adds 55 dB fixed gain directly to a microphone

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

Output Gain value of 0dB. This output is adjustable from -20dB to 20dB

Adjust the balance of this and the previous option so they are matched in level for nominal input to your recorder from the AUX output

DH30 Product Manual

S

ECTION

A

UTO

M

IX

-M

INUS AND

A

COUSTIC

E

CHO

C

ANCELLATION

M

IX

-M

INUS

/A

COUSTIC

E

CHO

C

ANCELLATION

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. Use the A

RROW

buttons to display

Echo Canceller

. Press E

NTER

.

2. Use A

RROW

buttons to display

Mix-Minus/AEC

.

3. Select

On

or

Off

, then press E

NTER

to activate your selection.

4. Press E

SC

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 Mix-

Minus/AEC function of the DH30.

19

Comrex Corporation

20

E

CHO

R

EDUCTION

EC T

RAIN

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 A

RROW

buttons to display

Echo Canceller

. Press E

NTER

.

2. Use the A

RROW

buttons to display

Echo Reduction

. Press E

NTER

.

3. Use the A

RROW

buttons to display the appropriate option:

Off, Soft,

Normal

(default)

, Aggressive

or

Max.

Press E

NTER

to activate your selection.

4. Press E

SC

to return to the previous menu level.

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 E

NTER

.

This sends a constant burst of white noise out of the C

ALLER

O

UT 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 read just your levels for an even lower reading OR adjust the amount of echo reduction

(see the previous section “Echo Reduction” ).

DH30 Product Manual

D

IAGNOSTICS

T

EST

S

IGNAL

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. Use the A

RROW

buttons to display

Echo Canceller

. Press E

NTER

.

2. Select D

iagnostics

. Press E

NTER

.

3. Use the A

RROW

buttons to select the desired readout.

4. Press E

NTER

to generate a test signal.

5. Press E

NTER

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.

When configuring your DH30, you can send a test signal through the monitor (Receive), through the telephone line (Transmit) or through both.

1. Use the A

RROW

buttons to display

Echo Canceller

. Press E

NTER

.

2. Use the A

RROW

buttons to select

Test Signal

. Press E

NTER

.

3. Use the A

RROW

buttons to select

Receive, Transmit

or

Both

.

4. Press E

NTER

to send the test signal.

5. To stop the signal, use the A

RROW

buttons to select

Off

.

21

22

Comrex Corporation

S

ECTION

C

USTOMIZING

Y

OUR

S

YSTEM

S

ETTING

C

ALLER

P

ROCESSING

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 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 1000 2500

250 715

Frequency

1645 3500

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.

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.

• Ratio options are: Bypass, 2:1, 3:1, 4:1, 6:1 and Limiter.

• Threshold is referenced to the level of the caller audio on the VU meter. Adjustable from –20 dBu to 20 dBu.

• Post gain adds gain to all audio to compensate for compression.

Adjustable from 0 to 20 dB.

• Attack sets the time required to compress when audio exceeds threshold. Adjustable from <1 to 50 ms.

• 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 ex pan sion of caller audio.

The expander has the following characteristics:

• Expansion ratio is adjustable in the following ratios: Bypass, 2:1,

3:1, 4:1 or 6:1.

• Threshold is referenced to the caller out level. Adjustable from

–50 dBu to 0 dBu.

• Expansion attack time adjustable from <1 to 50 ms.

• Expansion release time adjustable from 100 ms to 2000 ms.

23

24

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

Call er

Processing

menu, you may need to add echo re duc tion 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

O

N

button after the hybrid is already connected to the telephone line.

This initiates the same noise burst mentioned above and retrains the hybrid.

DH30 Product Manual

S

YSTEM

P

ARAMETERS

These parameters control the telephone connect and disconnect modes, remote control switching mode, quality of audio sent to the A

UX

O

UT

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 O

FF

LED goes out and the green O

N

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 E

NTER

.

2. Use the A

RROW

buttons to select

On

.

3. Press E

SC

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 O

N

LED goes out and the red O

FF

LED comes on. The DH30 disconnects on all re or der tones with a cadence. Auto disconnect may not func-

tion as de scribed with some PBX sys tems. Prob lems in auto-an swer mode may be caused by ring tim ing. Also, some PBX systems do not provide loop drop or loop reversal when dis con nect ing calls. If your PBX only pro vides reorder tone or busy sig nals, the call-progress func tion must be en abled for auto-dis con nect to function properly.

1. Select

Auto Disconnect

from the system menu and press E

NTER

.

2.Use the A

RROW

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 E

SC

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 E

NTER

. Then select

Momentary

or

Latching

and press E

NTER

.

25

26

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

R

ECORD

and C

UE

functions can only be activated by momentary clo sures.

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

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

A

UX

O

UT

and AES/EBU S

END

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 —

This option determines whether the

AES/EBU Input

is active, and if so, at what sampling rate it runs. Please note this option has changed in relation to the previous version of this product, which selected the sampling rate automatically. If you plan on using the AES/EBU I

NPUT

, you must select the sampling rate in this menu. If no AES/EBU signal is applied to the input, this option must remain

Off

. If the sampling rate is chosen incorrectly or if an AES/EBU signal is not applied after choosing a sampling rate, the product will malfunction. If the

AES/EBU Input

remains

Off

, the AES/EBU

O

UTPUT

will remain active, synchronized to an internal 32KHz sampling clock.

If an AES/EBU input is applied (and the correct sampling rate option is chosen), the AES/EBU output will synchronize to the input sampling rate clock.

Set Passcode —

The DH30 passcode can be user programmed. The default passcode is SSTT E

NTER

.

1. Use the A

RROW

buttons to display

System

. Press E

NTER

.

2. Use the A

RROW

buttons to display

Passcode

. Press E

NTER

.

3. You will be prompted for a new five character passcode. The

T

,

S

,

E

SC

, or E

NTER

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.

27

Comrex Corporation

S

ECTION

S

PECIFICATIONS

28

D

W

O

F

IMENSIONS

EIGHT

PERATING

RONT

P

T

ANEL

EMPERATURE

C

ONTROLS

R

EAR

P

ANEL

C

ONNECTORS

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

6.7lbs/3.04kg (dry)11.2lbs/5.08kg (shipping)

32-100°F/0-38°C

0-80% - Humidity

LCD programming display, E

NTER

/E

SC

/ ST programming buttons, monitor volume control, send-level LED bar meter, caller-level LED bar meter, record, cue, hybrid O

N

/O

FF

, buttons with status LEDs

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

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.

DH30 Product Manual

T

ELEPHONE

T

RANSMIT

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).

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%

29

30

Comrex Corporation

T

ELEPHONE

R

ECEIVE

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%

E

CHO

C

ANCELLATION

/M

IX

-

M

INUS

TAIL TIME: 120 milliseconds

NULL: 50dB

T

ELCO

C

ANCELLATION

TAIL TIME: 32 milliseconds

NULL: 55dB

DH30 Product Manual

S

ECTION

P

INOUTS

R

EMOTE

C

ONNECTOR

Pin

1

Description

Remote on *

Pin

14

Description

Remote on Indication **

2

3

Remote off *

Remote Record *

15

16

Remote off Indication **

Record Indication **

4 Remote Cue *

Switch/Indicator Common

17

18

Cue Indication **

Indicator Common

5

†

6

†

7

Select Preset 1/Send Mute *

Select Preset 2/Caller Mute *

19

24

25

Send Presence Indicator **

Caller Presence Indicator **

†

8

9

10

11

12

N/C

Unbalanced Send #

Unbalanced Caller ##

Unbalanced Aux Out ###

Select Preset 3/Monitor Mute*

20

21

22

23

Indicator Common

Unbalanced

Audio Common #

Unbalanced

Audio Common ##

Unbalanced

Audio Common ##

Switch Common

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

RS232 C

ONNECTOR

Pin

1

2

3

4

5

Description

N/C

TXD

RXD

N/C

GROUND

7

8

Pin

6

9

Description

N/C

N/C

N/C

N/C

31

Comrex Corporation

32

R

ECORD

C

ONTROL

Pin

1

4

5

2

3

Description

Start

N/C

N/C

Stop

Record Enable

Pin

6

7

8

9

Description

Start Common

N/C

Stop Common

Record Enable Common

L

INE

C

ONNECTOR

S

ET

C

ONNECTOR

Pin

1

*2

3

Description

To pin 6 of SET RJ11C

To pin 5 SET of RJ11C

Tip

Pin

4

*5

6

Description

Ring

To pin 2 of SET RJ11C

To pin 1 of SET RJ11C

*When the O

N

button is illuminated on the DH30, an “A-Lead Closure” is provided between pins 2 and 5 of the L

INE

and S

ET

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.

Pin

1

*2

3

Description

To pin 6 of LINE RJ11C

To pin 5 of LINE RJ11C

Ring

Pin

4

*5

6

Description

Tip

To pin 2 of LINE RJ11C

To pin 1 of LINE RJ11C

XLR C

ONNECTOR

Pin

1

2

3

Description

Ground

+ Phase audio

- Phase audio

Pin

Tip

Ring

Sleeve

Description

+ Phase audio

- Phase audio

- Phase audio

DH30 Product Manual

S

ECTION

S

ERIAL

C

OMMUNICATIONS

P

ROTOCOL

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 O

TE 1

Cue Status

Cue Off

Cue On

Cue Toggle

Record Status

Record Off

Record On

Record Toggle

Monitor Volume Up*

Monitor Volume Down

*no value give

CUE<cr>

CUE 0<cr>

CUE 1<cr>

Cue 2<cr>

REC<cr>

REC 0<cr>

REC 1<cr>

REC 2<cr>

VOLUP<cr>

VOLDWN<cr>

CUE 0 or CUE 1

CUE 0

CUE 1

CUE 0 or CUE 1

(toggled)

REC 0/1/2/3

(see note below)

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 table below:

2

3

Status Returned

0

1

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>

DH30 Product Manual

S

ECTION

9 F

LOW

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 L

INE

and S

ET

jacks are both input and output). The outputs are on the right.

DH30 Audio Flow

Send In

(XLR)

Send In

(DB25 Pin 9)

Mic/Line

Send In

Gain

+/-20

Full

Bandwidth

Send to Aux

Off

Aux Send

Gain

+/-20

Processed

Gain

+/-20

Aux Call

AES/EBU In

(XLR)

AES/

EBU

Send (left)

Cue (right)

Cue In

(XLR)

Telco Line

(RJ-11)

Mic/Line

Cue In

Gain

+/-20

Cue button

Telco Set

(RJ-11)

Send

Processing

Caller

Processing

Call Out

Gain

+/-20

Send (right)

Caller (left)

AES/

EBU

AES/EBU Out

(XLR)

Monitor

Volume

Gain

+18 to mute

2 W

Amp

Aux Out

(XLR)

Aux Out

(DB25 Pin 11)

Caller Out

(XLR)

Caller Out

(DB25 Pin 10)

Monitor

(1/4" Phono)

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Comrex Corporation

S

ECTION

C

OMPLIANCE

FCC P

ART

15 C

OMPLIANCE

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 equipmet 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.

36

FCC P

ART

68 C

OMPLIANCE

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.

DH30 Product Manual

IC C

OMPLIANCE

If you experience problems with this equipment, contact Comrex Corporation, 19 Pine Road, Devens, MA 01434 or by telephone at 978-784-1776 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.

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.

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Comrex Corporation

I

NTERNATIONAL

C

OMPLIANCE

(A

PPLIES 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 01434 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.

DH30 Product Manual

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ECTION

U

SER

-D

EFINED

P

RESETS

W

ORKSHEET

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

Caller

Submenu

Selections

Select Preset

Copy Preset

Recall Default

Send In Gain

Send In Preamp

Cue In Gain

Cue In Preamp

Call Out Gain

Aux Send Gain

Aux Call Gain

EQ

Compressor

Expander

Bass Boost

Caller Control

Noise Burst

Submenu

Parameters

Submenu

Ranges

Factory

Default

-20 to 20dB

Line

Mic

-20 to 20dB

Line

Mic

-20 to 20dB

-20 to 20dB

-20 to 20dB

Preset 1 n/a n/a

0dB

Line

0dB

Line

0dB

0dB

0dB

EQ Bypass

EQ Low Band

EQ Mid Band

Off

On

-20 to 20dB

-20 to 20dB

EQ High Band -20 to 20dB

Comp Ratio Bypass

2:1

3:1

On

0dB

0dB

0dB

Bypass

4:1

6:1

Limiter

Comp Threshold -20 to 20dB

Comp Post Gain -20 to 20dB

Comp Attack <1mS to 50mS

0dB

0dB

15mS

Comp Release 100 to 2000mS 500mS

Exp Ratio Bypass Bypass

2:1

3:1

4:1

6:1

Exp Threshold -50 to 0dB

Exp Attack <1mS to 50mS

-40dB

15mS

Exp Release 100 to 2000mS 500mS

0 to 30 0

0 to -30dB

Off

On

0dB

On

User

Preset 1

User

Preset 2

User

Preset 3

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Comrex Corporation

Menu

Categories

Echo

Canceller

System

Lock Panel

Submenu

Selections

Mix-minus/AEC

Echo Reduction

EC Train

Diagnostics

Test Signal

Auto Answer

Auto Disconnect

Remote Control

Remote Aux Pins

Send to Aux

AES/EBU

Set Passcode

Version**

Submenu

Parameters

Submenu

Ranges

Factory

Default

User

Preset 1

Off

On

Off

Loop Drop Only

Call Prog Only

Loop Drop + CP

Momentary

Latching

Mute Audio

Select Presets

Off

Processed

Full bandwidth

AES Off

32000 kHz

44100 kHz

48000 kHz

Off

On

Off

TERL

TEC

TNLP

TDB

Off On

On

Off Normal

Soft

Normal

Aggressive

Maximum

Off

Off

AERL

AEC

ANLP

ADB

Off

Receive

Transmit

Rcv & Transmit

Off

Off

Off

Momentary

Select Presets

Processed

AES Off

New Passcode SSTT Enter

Vx.x Date

Off Off

On--"L" will appear in lower right corner of screen

User

Preset 2

**Sub menu version will indicate the current version of code and the date implemented.

User

Preset 3

DH30 Product Manual

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ECTION

G

LOSSARY

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.

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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.

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.

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