ASTi ACU2 Manual

Advanced Simulation Technology inc.
500A Huntmar Park Drive
Herndon, Virginia 20170 USA
Tel. [phone] • Fax. [phone]
www.asti-usa.com
Advanced Simulation Technology inc.
500A Huntmar Park Drive, Herndon, Virginia 20170 USA
Revision L, Version 1 (December, 2017)
ACU2 Technical User Guide
Document: DOC-HW-ACU2-UG-L-1

Product Name: ACU2
ACU2 Technical User Guide
© Copyright ASTi 2017
Restricted Rights: Use, duplication, or disclosure by the Government is subject to restrictions as
set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software
clause at DFARS 252.227-7013.
This material may be reproduced by or for the U.S. Government pursuant to the copyright
license under the clause at DFARS 252.227-7013 (1994).
ASTi
500A Huntmar Park Drive
Herndon, Virginia 20170 USA

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Revision history
Date Revision Version Comments
10/4/2017 A 0 Convert original content to XML and edit for grammar
and accuracy.
12/8/2017 L 1 Edit "Analog In" figure in "Control input used as analog
input."

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Contents
1.0 Introduction 1
2.0 Physical description 3
2.1 ACU2 with bezels 3
2.2 ACU2 without bezels 4
2.3 Weight 4
2.4 Front panel 5
2.4.1 Audio interface: DB-15 pinout 5
2.5 Rear panel 6
2.5.1 Serial ports 6
2.5.2 Status indicator lights 7
2.5.3 DIP switch positions 8
2.5.4 ACENet connection 8
3.0 Audio input and audio output 10
3.1 Audio input 10
3.1.1 Microphone power 11
3.1.2 Input frequency response 12
3.2 Audio output 12
3.2.1 Audio isolation characteristics 13
3.2.2 Output frequency response 13
4.0 Control input and output 14
4.1 Control input 14
4.1.1 Control input used as a digital input 15
4.1.2 Control input used as analog input 15
4.2 Digital output 16
4.2.1 Digital output circuitry 16
5.0 Typical headset connections 17

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5.1 Mono headset connection 17
5.2 Stereo headset connection 17
6.0 Software configuration 18
7.0 Earth ground 19
8.0 Firmware updates 20
9.0 Rackmount ACU2s 21
9.1 Power daisy chain 22
10.0 Specifications 23
10.1 Power requirements 23
10.2 Memory devices 23
10.3 Temperature and humidity ranges 24
10.4 Reliability 24
11.0 Warranty information 25
11.1 Repairs and returns 25

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1.0 Introduction
The ACU2 is a compact, 48 kHz digital and audio distribution module that connects remotely
located operator stations and live radios to the ACENet network. The ACU2 is compatible with
the Telestra and Voisus platforms. The ACU2 provides low noise, analog-to-digital conversion,
and low-latency audio distribution.
The ACU2 integrates press-to-talk (PTT) units, volume controls, simulated communication pan-
els, hand-held terminals (HHTs), and live radios into the simulated communications envir-
onment.
The ACU2 supports the following features:
lStereo support: stereo operation (i.e., independent left and right output) is supported on a
single DB-15 connector, which reduces cabling complexity and installation footprint for
applications requiring stereo operators.
lCompact footprint: each device supports four configurable mono or stereo operator pos-
itions in a single compact unit, which fits easily on a desktop. Alternatively, rackmount
two devices side by side in 1U 19" rack space.
lHigh fidelity audio: 48 kHz digital audio and balanced pro-audio interfaces.
lSoftware-based configuration: software-adjustable amplifier or preamplifier gains and
microphone power for easy, direct connection to military and commercial headsets and a
wide variety of audio and communication systems and peripherals.
lSerial data ports: control interface for ASTi HHTs, simulated panels, and live radio con-
trol.
lIntegrated I/O: configurable digital and analog input/output (I/O) for direct connection of
PTT units, volume control, switch detection, radio PTT activation, and other control
applications.
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ACU2 Technical User Guide (Rev. L, Ver. 1)

The following figure shows an example of an ACU2 hardware configuration:
Figure 1: ACU2 hardware configuration
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ACU2 Technical User Guide (Rev. L, Ver. 1)

2.0 Physical description
The following sections provide a physical description of the ACU2, including diagrams with
and without bezels, a list of specifications, and diagrams and descriptions of the front and rear
panels.
2.1 ACU2 with bezels
The ACU2 has two bezels, encompassing the front and rear panels. This ACU2 is Conformitè
Europèene (CE)/Restriction of Hazardous Substances (RoHS) certified. Removing the bezels
voids the CE certification. The following figure shows the ACU2 front bezel:
Figure 2: ACU2 front bezel
The following figure shows ACU2 height and width dimensions:
Figure 3: ACU2 height and width dimensions
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ACU2 Technical User Guide (Rev. L, Ver. 1)

The following figure shows ACU2 bezel side dimensions:
Figure 4: ACU2 bezel side dimensions
2.2 ACU2 without bezels
Older versions of the ACU2 do not have bezels. The following table shows the specification for
ACU2s without bezels:
Specification Description
Length 7.5"
Width 7"
Height 1.55"
Table 1: Specifications for ACU2s without
bezels
2.3 Weight
A packaged ACU2 weighs 2 lbs. The power supply included with the ACU2 weighs 0.5 lbs.
4 Copyright © 2017 Advanced Simulation Technology inc.
ACU2 Technical User Guide (Rev. L, Ver. 1)

2.4 Front panel
The following figure shows the ACU2's front panel:
Figure 5: Front panel of ACU2 without bezel
The front panel features four DB-15 connectors that are compatible with a variety of audio and
press-to-talk (PTT) devices.
2.4.1 Audio interface: DB-15 pinout
The following figure shows a DB-15 pinout for the ACU2 audio interface:
Figure 6: Interface connection DB-15 female
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ACU2 Technical User Guide (Rev. L, Ver. 1)

2.5 Rear panel
The following figure shows the ACU2 rear panel:
Figure 7: Rear panel of ACU2 without bezels
Number Description
Power Out: for use with the power daisy chain
Power In: for use with the ACU2 power supply, included
Earth grounds
Serial ports
Status indicator lights
Dual in-line package (DIP) switches
ACENet connection
Table 2: Rear panel callouts
2.5.1 Serial ports
The ACU2 has two serial ports that provide a control interface for ASTi hand-held terminals
(HHTs), simulated panels, and live radio control. The following figure shows an RJ-12 female
serial connection in RS-422 mode:
Figure 8: RJ-12 pin out: RS-422 mode
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ACU2 Technical User Guide (Rev. L, Ver. 1)

The following figure shows an RJ-12 female serial connection in RS-232 mode:
Figure 9: RJ-12 pin out: RS-232 mode
2.5.2 Status indicator lights
The ACU2 LED indicator lights display ACU2 status:
LED Lights Location Status
Flashing green Bottom Normal operation.
Solid green Bottom The ACU2 started up properly, but the ACENet is disconnected.
Red Top Internal board failure.
Table 3: Status indicator lights
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ACU2 Technical User Guide (Rev. L, Ver. 1)

2.5.3 DIP switch positions
Dual in-line package (DIP) switches toggle between normal operation mode and firmware
update mode. For additional guidance, see Section 8.0, "Firmware updates" on page20.
The following figure shows DIP switch positions:
Position Status
Position 1 down allows for firmware updates.
Default position for normal operation.
Table 4: DIP switch positions
2.5.4 ACENet connection
The ACU2's ACENet port connects to an ACENet-compatible switch via a Category 5e
(CAT5e) cable or better.
Device Cable Length
ACU2 100 meters (328 feet)
Telestra or server 100 meters (328 feet)
Table 5: Maximum cable length to ACENet switch
Important: Customer-made cables are the primary reason for product failure. ASTi recom-
mends high-quality, manufactured CAT5e cables.
Alternatively, the ACU2 can connect directly to the Telestra or Voisus server using a crossover
cable. The ACU2 does not support daisy chaining to additional units or internal switching across
networks.
8 Copyright © 2017 Advanced Simulation Technology inc.
ACU2 Technical User Guide (Rev. L, Ver. 1)

2.5.4.1 RJ-45 ACENet connection pinout
The following figure shows an RJ-45 ACENet connection pinout:
Figure 10: RJ-45 ACENet connection pin out
2.5.4.2 ACENet indicator lights
The ACENet LED indicator lights display the port status:
LED Light Status
Solid green Network link
Flashing green Network activity
Solid or flashing amber One ACENet device per network functions as the ACENet master and is iden-
tified with a flashing amber light. All other ACENet devices should report a solid
amber light.
Table 6: ACENet indicator lights
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ACU2 Technical User Guide (Rev. L, Ver. 1)

3.0 Audio input and audio output
The following sections describe ACU2 audio input and output specifications.
3.1 Audio input
The following table shows ACU2 audio input characteristics and values:
Input Impedance 4.6 k
Input Level 3.25 Vpp max (6.5 Vpp differential)
Input Gain -8 dB, +2 dB to +57 dB, software configurable
Note: The ACU2 gain covers a total range of 65 dB. Between +2 dB and +57 dB,
the gain can be set in 1 dB steps. A value of -8 dB is available for input signals
greater than line level. The range -8 dB to +2 dB cannot be selected as a function
of design.
Microphone Power +12.5 VDC, software-enabled
Frequency Response 20 Hz to 20 kHz, +/- 1.5 dB
Table 7: Audio input characteristics
10 Copyright © 2017 Advanced Simulation Technology inc.
ACU2 Technical User Guide (Rev. L, Ver. 1)

3.1.1 Microphone power
In Telestra systems, microphone power is configured in the Remote Management System
(RMS). Input levels can be adjusted in the RMS to accommodate line level signals as well as
microphone level signals. R1 and R2 connections are only active when power mode is enabled
in the software:
Figure 11: Microphone power diagram
Caution: Do not connect a microphone requiring phantom power to an ACU2 device, as this
will damage the microphone. If you are unsure of the difference between microphone power
and phantom power, contact the microphone manufacturer or ASTi before connecting equip-
ment. Most military headsets use microphone power.
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ACU2 Technical User Guide (Rev. L, Ver. 1)

3.1.2 Input frequency response
The following figure shows an ACU2's input frequency response:
Figure 12: ACU2 input frequency response
3.2 Audio output
The following table shows an ACU2's audio output:
Output Impedance 10 Ohms
Output Current 0.201 A at 8 Ohms
Output Gain -25 dB to +10 dB
Output Level 1.61 VAC rms into 8 Ohms
Output Power 0.32 W at 8 Ohms
Frequency Response 20 Hz to 20 kHz
Max Output Signal 10 Vpp
Figure 13: ACU2 audio output
12 Copyright © 2017 Advanced Simulation Technology inc.
ACU2 Technical User Guide (Rev. L, Ver. 1)

3.2.1 Audio isolation characteristics
The following table shows audio isolation characteristics:
Between Isolation Frequency
Ch. 1 left to Ch. 1 right output channels -81 dB at + 4 dBu 20 Hz to 20 kHz
Ch. 1 to Ch. 2 output channels -77 dB at +4 dBu
Ch. 1 output to Ch. 1 input > -100 dB at +4 dBu
Ch. 1 output to Ch. 2 input
Ch. 1 input to Ch. 2 input
Table 8: Audio isolation characteristics
3.2.2 Output frequency response
The following figure shows an ACU2's output frequency response:
Figure 14: ACU2 output frequency response
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ACU2 Technical User Guide (Rev. L, Ver. 1)