Avid Technology HD I/O User manual

Pro Tools | HD I/O Guide
®

Legal Notices
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This guide may not be duplicated in whole or in part without
the written consent of Avid.
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Response, Avid DNA, Avid DNxcel, Avid DNxHD, Avid DS
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Beat Detective, Beauty Without The Bandwidth,
Beyond Reality, BF Essentials, Bomb Factory, Bruno, C|24,
CaptureManager, ChromaCurve, ChromaWheel,
Cineractive Engine, Cineractive Player, Cineractive Viewer,
Color Conductor, Command|8, Control|24, Cosmonaut Voice,
CountDown, d2, d3, DAE, D-Command, D-Control, Deko,
DekoCast, D-Fi, D-fx, Digi 002, Digi 003, DigiBase,
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Link & Sync, ListSync, LKT-200, Lo-Fi, MachineControl,
Magic Mask, Make Anything Hollywood,
make manage move|media, Marquee, MassivePack,
MassivePack Pro, Maxim, Mbox, Media Composer,
MediaFlow, MediaLog, MediaMix, Media Reader,
Media Recorder, MEDIArray, MediaServer, MediaShare,
MetaFuze, MetaSync, MIDI I/O, Mix Rack, Moviestar,
MultiShell, NaturalMatch, NewsCutter, NewsView,
NewsVision, Nitris, NL3D, NLP, NSDOS, NSWIN, OMF,
OMF Interchange, OMM, OnDVD, Open Media Framework,
Open Media Management, Painterly Effects, Palladiium,
Personal Q, PET, Podcast Factory, PowerSwap, PRE,
ProControl, ProEncode, Profiler, Pro Tools, Pro Tools|HD,
Pro Tools LE, Pro Tools M-Powered, Pro Transfer,
QuickPunch, QuietDrive, Realtime Motion Synthesis,
Recti-Fi, Reel Tape Delay, Reel Tape Flanger,
Reel Tape Saturation, Reprise, Res Rocket Surfer, Reso,
RetroLoop, Reverb One, ReVibe, Revolution, rS9, rS18,
RTAS, Salesview, Sci-Fi, Scorch, ScriptSync,
SecureProductionEnvironment, Shape-to-Shape,
ShuttleCase, Sibelius, SimulPlay, SimulRecord,
Slightly Rude Compressor, Smack!, Soft SampleCell,
Soft-Clip Limiter, SoundReplacer, SPACE, SPACEShift,
SpectraGraph, SpectraMatte, SteadyGlide, Streamfactory,
Streamgenie, StreamRAID, SubCap, Sundance,
Sundance Digital, SurroundScope, Symphony, SYNC HD,
SYNC I/O, Synchronic, SynchroScope, Syntax,
TDM FlexCable, TechFlix, Tel-Ray, Thunder, TimeLiner,
Titansync, Titan, TL Aggro, TL AutoPan, TL Drum Rehab,
TL Everyphase, TL Fauxlder, TL In Tune, TL MasterMeter,
TL Metro, TL Space, TL Utilities, tools for storytellers, Transit,
TransJammer, Trillium Lane Labs, TruTouch, UnityRAID,
Vari-Fi, Video the Web Way, VideoRAID, VideoSPACE,
VTEM, Work-N-Play, Xdeck, X-Form, and XMON are either
registered trademarks or trademarks of Avid Technology, Inc.
in the United States and/or other countries.
Bonjour, the Bonjour logo, and the Bonjour symbol are
trademarks of Apple Computer, Inc.
Thunderbolt and the Thunderbolt logo are trademarks of Intel
Corporation in the U.S. and/or other countries.
This product may be protected by one or more U.S. and non-
U.S. patents. Details are available at www.avid.com/patents.
Product features, specifications, system requirements, and
availability are subject to change without notice.
Guide Part Number 9320-65263-00 REV B 08/14

Contents iii
Chapter 1.
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Pro Tools | HD I/O Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
What’s Included . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
System Requirements and Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
About This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
About www.avid.com . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 2.
Pro Tools | HD I/O Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Pro Tools | HD I/O Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Pro Tools | HD I/O Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 3.
Connecting Pro Tools | HD I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Connecting Pro Tools | HD I/O to Pro Tools | HDX Cards . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Connecting Pro Tools | HD I/O to a Pro Tools | HD Native Card . . . . . . . . . . . . . . . . . . . . . 16
Connecting Pro Tools | HD I/O to Pro Tools|HD Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Chapter 4.
Configuring Pro Tools | HD I/O in Pro Tools | HD Software . . . . . . . . . 21
Hardware Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Configuring HD I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Using Input Trims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Chapter 5.
Adding or Removing I/O Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Removing an I/O Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Installing an Expansion I/O Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Chapter 6.
Pinout Diagrams for the DB-25 Connectors . . . . . . . . . . . . . . . . . . . . . . . 37
Analog Output DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Analog Input (+4 dBu) DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Analog Input (–10dBV) DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
AES/EBU DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
TDIF DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter 7.
HD I/O Calibration Mode Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
About Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Calibrating the HD I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Switching Jumpers on the Analog Output Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Contents

Pro Tools | HD I/O Guideiv
Chapter 8.
はじめに . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Pro Tools | HD I/O
の機能 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
内容 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
システム要件と互換性 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
登録 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
このマニュアルについて . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
www.avid.com
について . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Chapter 9. Pro Tools | HD I/O
の概要 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Pro Tools | HD I/O
：フロン パネル . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Pro Tools | HD I/O
のバックパネル . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Chapter 10. Pro Tools | HD I/O
を接続する . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Pro Tools | HD I/O
を
Pro Tools | HDX
カードに接続する . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Pro Tools | HD I/O
を
Pro Tools | HD Native
カードに接続する . . . . . . . . . . . . . . . . . . . . . . . 63
Pro Tools | HD I/O
を
Pro Tools|HD
カードに接続する . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Chapter 11. Pro Tools | HD Software
で
Pro Tools | HD I/O
を設定する . . . . . . . . 67
ハードウェア設定 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
HD I/O
を設定する . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
入力モードの使用方法 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Chapter 12. I/O
カードを追加する、または取り外す . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
I/O
カードを取り外す . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
拡張
I/O
カードをインス ールする . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Chapter 13. DB-25
コネクターのピ アウト図 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
アナログ・アウ プッ
DB-25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
アナログ・インプッ （
+4dBu
）
DB-25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
アナログ・インプッ （
–10dBV
）
DB-25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
AES/EBU DB-25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
TDIF DB-25
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Chapter 14. HD I/O
のキャリブレーショ ・モードの説明 . . . . . . . . . . . . . . . . . . . . . . . . . 89
キャリブレーションについて . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
HD I/O
をキャリブレー する . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
アナログ・アウ プッ ・カードのジャンパーを切り替える . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Appendix A. Compliance Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Environmental Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
EMC (Electromagnetic Compliance) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Safety Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Chapter 1: Introduction 1
Chapter 1: Introduction
Pro Tools
®
|HDI/ObyAvid
®
is a multi-channel
digital audio interface designed for use with
Pro Tools
®
| HDX, Pro Tools
®
| HD Native, and
Pro Tools
®
| HD systems. HD I/O features 24-bit
analog-to-digital (A/D) and digital-to-analog
(D/A) converters, and supports sample rates of up
to 192 kHz.
HD I/O comes in three standard configurations:
• 8 x 8 x 8 (8 analog in, 8 analog out, and 8 dig-
ital in and out)
• 16 x 16 analog in and out
• 16 x 16 digital in and out
You can also add or remove analog (ADC and
DAC) and digital cards for custom configurations.
Pro Tools | HD I/O Features
HD I/O provides up to sixteen discrete channels of
audio input and output, each with a four-segment
LED meter. The total available analog and digital
I/O is dependent on the configuration of Analog
and Digital Expansion I/O cards installed in
HD I/O.
Analog I/O
• Up to 16 channels of 24-bit D/A and A/D con-
verters for superior analog input and output at
sample rates of 44.1 kHz, 48 kHz, 88.2 kHz,
96 kHz, 176.4 kHz, and 192 kHz with Analog In
and Analog Out HD I/O cards
• Soft Clip and Curv limiting circuits to protect
against clipping on analog input
Digital I/O
• Up to 16 channels of 24-bit digital I/O, using
AES/EBU, TDIF DB-25, or Optical at sample
rates of 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,
176.4 kHz, and 192 kHz with a Digital HD I/O
card
• Real-time sample rate conversion on digital in-
puts with a Digital I/O card (up to sixteen chan-
nels of AES/EBU, Optical, or TDIF)
• Support for S/MUX Optical for sample rates of
88.2 kHz and higher
• Support for 2 channels of S/PDIF Optical
(enclosed) with sample rates of up to 96 kHz
• 2 channels of AES/EBU I/O (enclosed) with
support for sample rates up to 192 kHz
• 2 channels of 24-bit-capable S/PDIF I/O
(enclosed) with support for sample rates up to
192 kHz

Pro Tools | HD I/O Guide2
Synchronization
• Loop Sync input and output for connecting addi-
tional Avid HD audio interfaces and peripherals
• External Clock input and output for synchroniz-
ing HD I/O with external Word Clock devices
Expandability
• Optional addition of I/O cards to expand analog
or digital I/O
• Simultaneous use of multiple Avid HD audio in-
terfaces to further expand system input and out-
put
What’s Included
• Pro Tools | HD I/O audio interface
• AC power cable
• DigiLink Mini cable (18 inches [0.46m])
• DigiLink Mini adapter
• BNC cable (18 inches [0.46m])
• Pro Tools | HD I/O Guide
• Health and Safety Guide
• Registration Information Card
System Requirements and
Compatibility
Avid can only assure compatibility and provide
support for hardware and software it has tested and
approved.
For complete system requirements and a list of
qualified computers, operating systems, hard
drives, and third-party devices, visit:
www.avid.com/compatibility
Registration
Review the enclosed Registration Information
Card and follow the instructions on it to quickly
register your purchase online. By registering, you
become eligible to receive the following:
• Technical support information
• Software update and upgrade notices
• Hardware warranty information
Hardware Warranty
Your warranty can be found on the Registration
Information Card.

Chapter 1: Introduction 3
About This Guide
This guide provides a basic overview of
Pro Tools | HD I/O features and functionality.
For hardware installation instructions for your
Pro Tools | HDX hardware, see the
Pro Tools | HDX Card Installation Guide.
For hardware installation instructions for your
Pro Tools | HD Native hardware, see the
Pro Tools | HD Native Installation Guide.
For hardware installation instructions for your
Pro Tools|HD hardware, see the Pro Tools|HD
User Guide.
For Pro Tools software installation instructions,
see the Pro Tools | Software Installation Guide.
For additional information about using Pro Tools
software, see the Pro Tools Reference Guide (in
Pro Tools, choose
Help > Pro Tools Reference
Guide
).
Conventions Used in This Guide
All of our guides use the following conventions to
indicate menu choices and key commands:
:
The names of Commands , Options , and Settings
that appear on-screen are in a different font.
The following symbols are used to highlight
important information:
Convention Action
File > Save Choose Save from the
File menu
Control+N Hold down the Control key
and press the N key
Control-click Hold down the Control key
and click the mouse button
Right-click Click with the right
mouse button
User Tips are helpful hints for getting the
most from your system.
Important Notices include information that
could affect your data or the performance of
your system.
Shortcuts show you useful keyboard or mouse
shortcuts.
Cross References point to related sections in
this guide and other Pro Tools guides.

Pro Tools | HD I/O Guide4
About www.avid.com
The Avid website (www.avid.com) is your best
online source for information to help you get the
most out of your Pro Tools system. The following
are just a few of the services and features available.
Product Registration Register your purchase
online.
Support and Downloads Contact Avid Customer
Success (technical support); download software
updates and the latest online manuals; browse the
Compatibility documents for system requirements;
search the online Knowledge Base or join the
worldwide Pro Tools community on the User
Conference.
Training and Education Study on your own using
courses available online or find out how you can
learn in a classroom setting at a certified Pro Tools
training center.
Products and Developers Learn about Avid prod-
ucts; download demo software or learn about our
Development Partners and their plug-ins, applica-
tions, and hardware.
News and Events Get the latest news from Avid or
sign up for a Pro Tools demo.

Chapter 2: Pro Tools | HD I/O Overview 5
Chapter 2: Pro Tools | HD I/O Overview
This chapter describes the front and back panel features of the Pro Tools | HD I/O.
Pro Tools | HD I/O Front Panel
Power Switch and LED Ring
This button turns HD I/O on and off. The LED ring
around the power button will light green or orange
to indicate the system status:
Green LED Ring Indicates that the unit has pow-
ered up successfully and is connected to an active
system.
Orange LED Ring Indicates that the unit has
power, but the computer it is connected to is shut
down.
Sample Rate
These LEDs display the current sample rate of the
HD I/O internal clock: 44.1 kHz, 48 kHz,
88.2 kHz, 96 kHz, 176.4 kHz, or 192 kHz. The
sample rate can be set in Pro Tools when you cre-
ate a new session, or in the Hardware Setup or
Playback Engine dialogs if no session is open.
HD I/O Front Panel

Pro Tools | HD I/O Guide6
Loop Master LED
The LOOP MASTER LED indicates which audio
interface is the master peripheral. The Loop Mas-
ter LED will be continuously lit on the current
Loop Master peripheral only, and unlit on all other
peripherals. (Only one Avid HD peripheral can be
Loop Master at a time.) The Loop Master LED will
always be lit with a single interface.
With HDX hardware, Loop Master defaults to the
first audio interface connected to DigiLink Mini
Port 1 on the first card in the system.
With HD Native hardware, Loop Master defaults
to the first audio interface connected to DigiLink
Mini Port 1 on the HD Native card.
For Pro Tools|HD systems, Loop Master defaults
to the first audio interface connected to the pri-
mary, or “core” Pro Tools|HD card. On
Pro Tools|HD (for PCIe), this is the Accel Core
card. On Pro Tools|HD (for PCI), this is the HD
Core card.
Sync Mode LEDs
The SYNC MODE LEDs indicate the current
Clock Source as set in Pro Tools.
INT (Internal) Indicates the HD I/O sample clock is
generated by its internal clock, as determined by
the session Sample Rate.
DIG (Digital) Indicates that an external AES/EBU,
TDIF, Optical (ADAT), Optical (ADAT S/MUX),
or S/PDIF device is providing system clock. If no
valid clock source is detected, HD I/O will switch
to internal clock, the DIG LED will flash, and an
error message will appear on-screen in Pro Tools.
LOOP Indicates that the HD I/O is slaving to an-
other Avid HD audio interface or SYNC peripheral
using Loop Sync.
EXT (External) Indicates that the HD I/O is using
the EXT CLOCK IN port for system synchroniza-
tion.
When synchronized to Word Clock, External
Clock input and output do not have to be at the
Word Clock rate. EXT CLOCK IN synchroniza-
tion will typically be 1x the current session sample
rate. However, for sample rates higher than 48
kHz, HD I/O generates a choice of 1x, 2x, or 4x of
a base rate of 44.1 kHz or 48 kHz, as
follows:
Meters
These four-segment LEDs indicate signal level for
each of the sixteen channels. The top row of meters
indicates input levels, and the bottom row shows
output levels. These meters are calibrated at –42
dB, –18 dB, –6 dB, and 0 dB,
respectively.
Session Sample Rate Word Clock Support
44.1 kHz 44.1 kHz
48 kHz 48 kHz
88.2 kHz 88.2 kHz
44.1 kHz
96 kHz 96 kHz
48 kHz
176.4 kHz 176.4 kHz
44.1 kHz
192 kHz 192 kHz
48 kHz
Note that 0 dB is not to be confused with clip-
ping; use the on-screen meters in Pro Tools
to determine whether a signal is clipping.

Chapter 2: Pro Tools | HD I/O Overview 7
Pro Tools | HD I/O Back Panel
Although the HD I/O is a sixteen-channel audio in-
terface, it has up to 94 inputs and outputs available
through its various back panel
connectors.
HD I/O comes in three standard configurations:
• 8 x 8 x 8 analog and digital in and out
• 16 x 16 analog in and out
• 16 x 16 digital in and out
Input and Output Cards
The HD I/O features four bays for HD I/O
Expansion cards. With the standard 8 x 8 x 8 con-
figuration, bays 1–3 contain Analog In, Analog
Out, and Digital I/O cards, respectively. The fourth
bay (as shown in this 8 x 8 x 8 configuration) is an
expansion bay, for which you can purchase an ad-
ditional Expansion I/O card of your choice.
By installing an optional AD Expansion card, DA
Expansion card, or Digital Expansion card, you
can add even more I/O capacity (up to a maximum
possible 110 inputs and outputs). See Chapter 5,
“Adding or Removing I/O Cards.”
HD I/O Back Panel, 8 x 8 x 8 configuration shown
964530300294856
WORD CLOCK LOOP SYNC
PRIMARY PORT
EXPANSION PORT
IN
OUT
AC ~ 100-240V;50-60HZ; A
S/PDIF
IN
OUT
AES/EBU
INPUT
AES/EBU
OUTPUT
OPTICAL
IN OUT
ACCESSORY
12345678
ANALOG INPUT
+4 dBu BALANCED -10 dBV BALANCED
12345678
ANALOG OUTPUT
BALANCED
DIGITAL I/O
AES/EBU
ADAT
IN
TDIF I/O
ADAT
OUT
Bay 2: Analog Out card
Bay 1: Analog In card Bay 3: Digital I/O card
Bay 4: Empty for Optional card
Enclosure
Input and Output cards for 192 I/O are not
supported in HD I/O.

Pro Tools | HD I/O Guide8
Analog Input
The HD I/O Analog In card contains connectors
for analog audio input with 24-bit, 192 kHz A/D
converters. Input is provided through two discrete
DB–25 connectors (one for +4 dBu sources, and
the other for –10 dBV sources). You can connect
sources at both operating levels and choose be-
tween them from within Pro Tools.
+4 dBu Balanced Provides eight balanced input
channels at +4 dBu nominal operating levels.
–10 dBV Balanced Provides eight balanced input
channels at –10 dBV nominal operating levels.
For wiring information, see Chapter 6, “Pinout Di-
agrams for the DB-25 Connectors.”
For each channel, you can select input level from
within the Hardware Setup dialog (see “Hardware
Setup” on page 21).
Input Trims
The Input Trims below the DB–25 connectors are
used to individually calibrate each channel’s input
level. See “Input Trims” on page 30.
Additionally, the Limiter function helps avoid dig-
ital clipping (see“Limiter” on page 26).
Analog Output
The HD I/O Analog Out card contains a single
DB–25 connector and Output Trims for eight
channels of analog audio output. These balanced
outputs operate at +4 dBu levels. See Chapter 6,
“Pinout Diagrams for the DB-25 Connectors.”
Output Trims
The Output Trims below the DB–25 connector are
used to individually calibrate each channel’s out-
put level. For more information, see Chapter 7,
“HD I/O Calibration Mode Instructions.”
Most consumer electronics operate at –10 dBV
levels, and may not feature balanced inputs and
outputs. You can connect –10 dBV signals to
the –10 dBV inputs, but you will need to make
sure that the negative terminals are not con-
nected.
For –10 dBV gear, you can switch a jumper
on Analog Output cards (on a channel-by-
channel basis) from the default Hi position
to Lo for a –6 dB pad. You can then adjust
the Trim pot for the corresponding output
channels by an additional –4 dB to accom-
modate –10 dBV gear. For more informa-
tion, see Chapter 7, “HD I/O Calibration
Mode Instructions.”

Chapter 2: Pro Tools | HD I/O Overview 9
Digital I/O
The Digital I/O card contains connectors for eight
channels each of AES/EBU I/O, TDIF I/O, and
Optical (ADAT) I/O. Only one digital format can
be used at a time.
AES/EBU DB–25 connectors for eight channels of
AES/EBU input and output. Each of the paired
channels is a balanced three-conductor signal, and
supports 192 kHz sample rates in single-wire
mode up to eight channels. Dual-wire mode uses
two HD I/O physical I/O channels of AES/EBU
I/O to carry each single stream of 176.4 kHz or
192 kHz audio. Therefore, only four simultaneous
channels of AES/EBU I/O are available at
176.4 kHz or 192 kHz.
TDIF DB–25 connectors for eight channels of
TDIF input and output. Conforms to standard
eight-channel TDIF pinouts. For more informa-
tion, see Chapter 6, “Pinout Diagrams for the DB-
25 Connectors.”
Optical (ADAT) Dedicated, eight-channel 24-bit
capable Optical ports (up to 48 kHz), with real-
time sample rate conversion on input (only). Note
that Optical S/PDIF is not supported with the Dig-
ital I/O card and is supported with the enclosed
Optical ports only (for more information, see “Op-
tical (ADAT) [Encl]” on page 10).
The inputs on the Digital I/O card feature real-time
sample rate conversion. For example, you can
stream audio with a sample rate of 44.1 kHz into a
96 kHz session.
Enclosure Connectors
The right half of the back panel of HD I/O features
a set of non-removable connectors that are
mounted to the enclosure.
These connectors include two channels of
AES/EBU IO, Optical I/O (for another eight chan-
nels of ADAT format, or two channels of Optical
S/PDIF), and two channels of coaxial S/PDIF I/O.
On-screen, these connectors are identified as
AES/EBU [Encl], Optical (ADAT) [Encl], Optical
(S/PDIF) [Encl], and S/PDIF [Encl].
Other connectors include Loop Sync, External
Clock, and ports for attaching the HD I/O to HDX,
HD Native, or Pro Tools|HD cards, or to other
Avid HD audio interfaces.
We recommend using Avid DB-25 TDIF
cables for optimum compatibility.
For more information, see“Hardware Setup”
on page 21.

Pro Tools | HD I/O Guide10
AES/EBU [Encl]
These are balanced, three-conductor XLR connec-
tors that accept and output a stereo, 24-bit
AES/EBU audio signal. These two ports support
up to 192 kHz sample rates.
Optical (ADAT) [Encl]
These Optical ports provide up to eight channels of
Optical (ADAT) input and output, or two channels
(stereo) optical S/PDIF input and output. Optical
(ADAT) mode supports sample rates up to 48 kHz.
Using S/MUX, these Optical ports support provide
up to four channels of Optical S/MUX input and
output at sample rates of 88.2 and 96 kHz, and up
to two channels of Optical S/MUX input and out-
put at sample rates of 176.4 and 192 kHz. In TOS-
Link mode, the ports support two channels of Op-
tical input and output at sample rates up to 96 kHz.
About Lightpipe-Compatible Devices
Lightpipe is an industry standard, eight-channel
optical digital audio connection created by Alesis.
Lightpipe is found on many devices, including Op-
tical (ADAT) decks, modular digital multitracks
(MDMs), A/D or D/A converters, S/MUX, and
digital consoles.
S/PDIF Digital In and Out
These are unbalanced RCA jacks that receive and
send two channels of S/PDIF audio. S/PDIF sup-
ports up to 24-bit audio, at sample rates up to 192
kHz.
DigiLink Mini Ports
PRIMARY PORT
Use the PRIMARY PORT to connect HD I/O to
HDX or HD Native cards using a DigiLink Mini
cable, or to Pro Tools|HD cards using a DigiLink
cable with a DigiLink Mini adapter.
The Primary port sends and receives 32 channels to
and from an HDX, HD Native, or Pro Tools|HD
card. Input and output channels 17–32 (if active)
are passed through to the EXPANSION PORT.
EXPANSION PORT
The EXPANSION PORT lets you connect an ad-
ditional Avid HD audio interface to HD I/O. The
EXPANSION PORT passes input and output
channels 17–32 to the expansion (or secondary)
audio interface.
This port is only available when HD I/O is con-
nected directly to an HDX, HD Native, or
Pro Tools|HD card. It is not available when the
HD I/O is connected to the Expansion Port on an-
other audio interface.
Configure HD I/O for ADAT S/MUX on the
enclosed ADAT port and also on the ADAT
port on the Digital I/O card to get 8 channels
at 88.2/96 kHz or 4 channels at
176.4/192 kHz.
To maintain data integrity and minimize jit-
ter, use only 75-ohm coaxial cable for
S/PDIF connections.

Chapter 2: Pro Tools | HD I/O Overview 11
DigiLink Mini Cables and Adapters
Avid provides various cables and adapters to con-
nect Avid HD audio interfaces to HDX,
HD Native, and Pro Tools|HD cards.
DigiLink Mini Cables
Use a DigiLink Mini cable to connect an HD I/O to
an HDX or HD Native card, or to other Avid HD
audio interface (such as another HD I/O).
There are five different lengths of DigiLink Mini
cables:
• 18 in (0.46m)
• 12 ft (3.6m) (sold separately)
• 25 ft (7.62m) (sold separately)
• 50 ft (15.25m), the maximum length sup-
ported for 176.4 kHz and 192 kHz sessions
(sold separately)
• 100 ft (30.5m), the maximum length sup-
ported by 88.2 kHz and 96 kHz sessions (sold
separately)
DigiLink Mini Adapters
Use a DigiLink cable with a DigiLink Mini adapter
to connect HD I/O to a Pro Tools|HD card. You
can also use a DigiLink Mini adapter to connect
HD I/O to legacy Pro Tools|HD audio interfaces
(such as 192 I/O).
There are two types of DigiLink Mini adapters:
• 12 in DigiLink Mini female to DigiLink male
• 12 in DigiLink Mini male to DigiLink female
Clock and Synchronization Ports
WD CLOCK IN and OUT
The Word Clock I/O ports are standard BNC con-
nectors that receive and output word clock signal.
These ports can be used to synchronize HD I/O
with any word clock-capable device.
Word Clock In can be configured by selecting it as
the Clock Source in the Hardware Setup dialog in
Pro Tools. Word Clock Out can also be configured
in the Hardware Setup dialog using the External
Clock Output selector.
For more information about DigiLink Mini
cables and adapters, visit the Avid website
(www.avid.com).
Because crucial timing data is passed
through the Loop Sync and Word Clock
ports, you should use high-quality, 75-Ohm
RG–59 cables for making connections.

Pro Tools | HD I/O Guide12
LOOP SYNC In and Out
Loop Sync is a dedicated clock loop for synchro-
nizing multiple Pro Tools|HD peripherals together
(multiple audio interfaces, or a SYNC HD and one
or more audio interfaces). Loop Sync technology
lets you synchronize to any digital peripheral con-
nected to any of the Pro Tools|HD audio interfaces
in your Pro Tools system. Loop Sync uses a word
clock signal based on sample rates of either
44.1 kHz or 48 kHz. As sample rate increases in
the system, Loop Sync continues to operate at a
base rate of 44.1 kHz or 48 kHz, depending upon
the higher rate.
The Loop Sync In and Out ports are standard BNC
connectors that output a 1x Word clock signal.
Loop Sync should only be used to chain multiple
Pro Tools|HD peripherals together (such as
Pro Tools|HD audio interfaces and SYNC HD).
AC Power
This connector accepts a standard AC power cable.
HD I/O is auto power-selecting (100V to 240V)
and will automatically work with a standard mod-
ular cable (IEC) to connect to AC power outlets in
any country.
Accessory Port
This port currently has no functionality.

Chapter 3: Connecting Pro Tools | HD I/O 13
Chapter 3: Connecting Pro Tools | HD I/O
Pro Tools | HD I/O provides up to sixteen channels
of analog and digital I/O with HD I/O with HDX,
HD Native, or Pro Tools|HD hardware.
HDX With Pro Tools | HDX hardware, HD I/O is
connected to the HDX card using a DigiLink Mini
cable. You can connect additional HD audio inter-
faces to your system using the Expansion port on
the back of HD I/O, the second DigiLink Mini Port
on the HDX card, or by using additional HDX
cards. See “Connecting Pro Tools | HD I/O to
Pro Tools | HDX Cards” on page 14.
HD Native With Pro Tools | HD Native hardware,
HD I/O is connected to the HD Native card using a
DigiLink Mini cable. You can connect additional
HD audio interfaces to your system using the Ex-
pansion port on the back of HD I/O or the second
DigiLink Mini Port on the HD Native card. See
“Connecting Pro Tools | HD I/O to a
Pro Tools | HD Native Card” on page 16.
Pro Tools|HD With Pro Tools|HD hardware,
HD I/O is connected to a Pro Tools|HD card
using a DigiLink cable with a DigiLink Mini
adapter. You can connect additional HD audio in-
terfaces to your system using the Expansion port
on the back of HD I/O or using additional
Pro Tools|HD cards. See “Connecting
Pro Tools | HD I/O to Pro Tools|HD Cards” on
page 18.
Rack Mounting HD Audio Interfaces
HD I/O and all Avid HD audio interfaces need
room at their sides to maintain proper air flow for
cooling. Do not block the sides of the unit or dis-
connect the internal fan. If the units are rack-
mounted in a case, remove the case lids or doors
before operating the system. Failure to do so can
result in the units overheating very quickly, which
can permanently damage sensitive
components.
For more information about installing HDX
cards, see the Pro Tools | HDX Installation
Guide .
For more information about installing the HD
Native card, see the Pro Tools | HD Native
Installation
Guide .
For more information about installing
Pro Tools|HD cards, see the Pro Tools|HD
User
Guide .

Pro Tools | HD I/O Guide14
Connecting Pro Tools | HD I/O to Pro Tools | HDX Cards
Each HDX card supports up to 64 channels of audio input and output. To get a full 64 channels of I/O, you
can connect up to four 16-channel HD I/O to an HDX card. Two of the interfaces connect directly to Dig-
iLink Mini Ports 1 and 2, and the other two HD I/O connect to the Expansion ports on first two HD I/O.
To connect HD I/O to an HDX card:
 Connect the HD I/O Primary Port to DigiLink Mini Port 1 on the HDX card using a DigiLink Mini ca-
ble.
To connect additional HD I/O audio interfaces:
1 After connecting the primary audio interface,
connect additional HD I/O (or other compatible
audio interfaces) by doing one of the following:
• Connect the Primary Port of the secondary in-
terface to the Expansion Port of the primary
interface with a DigiLink Mini cable.
• Connect the Primary Port of the secondary in-
terface to DigiLink Mini Port 2 on the HDX
card.
2 Repeat the preceding with additional HDX
cards.
3 Make the necessary Loop Sync connections
(see “Connecting Loop Sync” on page 14).
Connecting Loop Sync
If you are using two or more HD audio interfaces
or a SYNC peripheral, Loop Sync must be con-
nected to maintain proper clock synchronization
among the devices. For an example of connecting
multiple Avid HD audio interfaces, see Figure 2 on
page 15. For examples that include a SYNC pe-
ripheral, see the SYNC HD Guide.
To make Loop Sync connections:
1 Connect the Loop Sync Out of each interface to
the Loop Sync In of the next interface with a
BNC cable.
2 Connect the Loop Sync Out of the last interface
to the Loop Sync In of the primary interface or
SYNC peripheral with a BNC cable.
Figure 1. HD I/O connected to the DigiLink Mini Port 1 on an HDX card

Chapter 3: Connecting Pro Tools | HD I/O 15
Figure 2. Making DigiLink and Loop Sync connections with two HDX cards, one HD OMNI, and five HD I/Os
Second HDX card
First HDX card

Pro Tools | HD I/O Guide16
Connecting Pro Tools | HD I/O to a Pro Tools | HD Native Card
To connect HD I/O to an HD Native card:
 Connect the HD I/O Primary Port to DigiLink Mini Port 1 on the HD Native card using the included
DigiLink Mini cable.
To connect two HD I/Os to an HD Native card:
1 Connect the Primary Port to DigiLink Mini Port 1 on the HD Native card using the included DigiLink
Mini cable.
2 Connect the additional HD I/O (or other compatible Pro Tools audio interface) by doing one of the
following:
• Connect the Primary Port of the secondary interface to the Expansion Port of the primary
interface with an additional DigiLink Mini cable (or DigiLink to DigiLink Mini adapter).
• Connect the Primary Port of the secondary interface to DigiLink Mini Port 2 on the HD Native card.
3 Make the necessary Loop Sync connections (see “Connecting Loop Sync” on page 17).
Figure 3. HD I/O connected to the DigiLink Mini Port 1 on an HD Native card
PORT 1PORT 2